Anyone 4 Science

From Hydrogen to Tellurium - TELLURIUM

2012-01-03T03:08:00.000-08:00

Tellurium

This blog, being written for the International Year of Chemistry, taking one element each week has finally arrived at week 52 and element 52 Tellurium.

Although I spent 4 years studying Chemistry and many more working in the field, when I started this blog last year I realised that I had never heard of the 52nd element - Tellurium . How could that have happened I wondered.

During the year I realised that there were other elements with which I was not familiar. I learned a little more about some of them during the year.

I also came across other chemists who had had the same experience, one had even traveled the world to try to find out about the many rare and not generally studied elements.

So what of Tellurium? It appears in the same group as oxygen, sulphur and selenium and is a non metal, but Tellurium has some metal characteristics and is classified as a semi metal.

Tellurium is occasionally found as a free element but is usually found combined with Gold.

Tellurium and all its compounds are highly toxic.

In spite of its rarity and toxicity, it does have some uses in semiconductors and as alloys with other metals.

From Hydrogen to Tellurium - ANTIMONY

2012-01-03T02:46:00.000-08:00

Antimony
The 51st element is called Antimony. Its name comes from the Greek words anti and monos which mean "not alone" and its symbol Sb from its Latin name Stibium.

Metallic Antimony is an extremely brittle metal of a flaky, crystalline texture. It is bluish white and has a metallic lustre.

Antimony is sometimes found as a free element but more often as its sulphur compound Antimony Sulphide.

Antimony and many of its compounds are toxic so this limits its uses though it has in the past been used as coins. It isn't very suitable for use in coins as it wears away relatively easily.

Antimony is used in the electronics industry, in alloys with other metals and in batteries.

From Hydrogen to Tellurium - TIN

2012-01-03T02:30:00.000-08:00

Tin
The 50th element is one that is very familiar to most people - Tin. Long before children learn the word science they learn about Tin  - the container for storing biscuits and foods such as baked beans, fruit and pet food.

The scientific symbol for Tin  is Sn. This name comes from Stannum the latin word for Tin .

Known for thousands of years, Tin  was mixed with copper to make bronze.Tin  is a silvery white metal.

The cans which we call tin cans are not made of pure Tin  but are actually steel cans with a thin layer of Tin  covering them.Tin  is also used in solders.
Window glass is made by floating molten glass on molten Tin . This is known as the Pilkington Process.

Experiment of the week
To make a flat sheet of fat using molten ice.

You will need:
About 15 ice cubes
A plastic or metal tray
A saucepan or heat proof container
250g lard
Adult supervision

What to do:
Place the ice cubes in the tray and allow to melt. The melted ice should be a minimum of 1cm deep. Add more ice if necessary.
In the saucepan melt the lard.
Gently pour a thin layer of the molten lard onto the molten ice (water).
Allow to cool. Remove the sheet from the tray.
Make more sheets of lard as required.

From Hydrogen to Tellurium - INDIUM

2012-01-03T02:26:00.000-08:00

Indium
The 49th element is indium, another metal with a silvery white appearance. Like Cadmium, indium is a soft metal. It has a low melting point - 156°C and can be mixed with gallium to make an alloy which is liquid at room temperature

It is used for making some electronic components, as a replacement for silver in mirrors and as a solder.

The name indium comes from the word indigo. Indigo is a dark blue colourful often cited as being one of the rainbow colours.

Experiment of the week
Investigate the colour indigo

You will need:
a light source, the sun or a light bulb
A CD
Adult supervision

What to do:
shine the light on the back of the CD
You should see all the colours of the rainbow as the light is split into its constituent colours.

From Hydrogen to Tellurium - CADMIUM

2012-01-03T02:23:00.000-08:00

Cadmium
The 48th element is Cadmium and is symbolised using the letters Cd.
Cadmium is a silver metal, but although it is next to silver on the periodic table it's colourful is the only similar trait the two elements have.
Cadmium is a soft metal which can be easily cut with a knife. Another important thing to mow is that it is toxic and therefore it is unlikely that you will come across it in a school setting.

It's most common use is in Ni-Cd batteries - rechargeable batteries.

Experiment of the week
To compare Ni-Cd and NiMH (Nickel Metal hydride) batteries.

You will need
An AA Ni-Cd battery
a AA NiMH battery
2 2.5V light bulbs
2 bulb holders
2 AA battery holders with flying leads
4 crocodile clips
Timer
Adult supervision

What to do
Ensure the batteries are fully. Barged.
Make up 2 circuits with the bulbs in the bulb holders connected to the battery holders.
Insert the Ni-Cd battery into one circuit and the NiMH battery into the other circuit.both the lights should light.
Start the timer.
Measure how long both bulbs light for to measure which battery is the best.

From Hydrogen to Tellurium - SILVER

2012-01-03T02:20:00.000-08:00

Silver

Number 47 on the periodic table is silver, a well known metal which most of you will be familiar with. It has a characteristic "silver" colour. This metal is quite rare and therefore valuable. It is used in jewellery as it is malleable. The fact that it is very stable in air also increases it's suitability for use in jewellery and other decorative and useful items. Because it doesn't react with air it keeps it's nice shiny silvery appearance.

The chemical symbol for silver is Ag. This symbol comes from the Latin name for silver Argentum.

Silver is found as an ore so it can be mined in the same way as we mined the chocolate chips from cookies when we were investigating copper earlier in the year.

Silver has no known biological role and isn't found in the human body.

Silver doesn't support the growth of bacteria and is therefore often used for chalices where many people are going to drink from the same cup.

As well as being used in jewellery and silverware, silver is also used in photography, mirror production, for coins and dentistry. A compound of silver , silver iodide is used to get rain clouds to rain.

Silver forms compounds with the halides, hydrogen, fluorine, chlorine, bromine and iodine. It also forms compounds with covalent elements such as oxygen, sulphur,
Selenium and tellurium.

Experiment of the week
To see if bread soda solution or washing soda make a better silver cleaner.

You will need:
2 Aluminium foil trays
Washing soda
Bread soda
Hot water
2 pieces of silver equally tarnished
A spoon
A timer
Adult supervision

What to do:
Put apiece of dirty or tarnished silver into each aluminium foil tray. Foil containers used by take away restaurants for rice are ideal.
Put a spoon of washing soda into one tray and a spoon of bread soda into the other one.
Pour equal amounts of hot water into each container.
Start the timer.
After 2 minutes remove both pieces of silver and compare. Which cleaning solution resulted in the cleanest silver?
Report your findings below.

Additional experiment - Compare your home made cleaning solution to a commercially available one.

From Hydrogen to Tellurium - Palladium

2011-11-14T14:28:00.000-08:00

Palladium , Pd is the 46th element. Like the elements I wrote about for the last couple of weeks, palladium is also in the platinum metals group. It's uses are similar to those of rhodium - a catalyst in catalytic converters, electrical connections and jewellery.Palladium has no known biological role and is not present in the human body.

From Hydrogen to Tellurium - Rhodium

2011-11-14T14:17:00.000-08:00

Rhodium Rh at number 45 is another slivery white transition metal. It is also in the platinum group.My research tells me that it is used in alloys, jewellery, In electrical applications and as a catalyst. Rhodium is extracted from ore by industry. It is not present in the human body and though the metal itself is not toxic many rhodium compounds are toxic amdalso cause cancer.

From Hydrogen to Tellurium - RUTHENIUM

2011-10-30T13:05:00.000-07:00

Ruthenium

Calendar week 44 in this the International Year of Chemistry means element number 44 and that is Ruthenium with the chemical symbol Ru.. This transition metal has 44 electrons and therefore is in 44th position. This white metal is often grouped with rhodium, palladium, osmium, iridium, and platinum to make up the Platinum group metals.

Ruthenium doesn't react with air at normal temperatures and because of this it doesn't tarnish.
It was first discovered in Russia in the mid 1800s and was named after the latin name for Russia - Ruthenia. Ruthenium is sometimes found as a free metal, often along with other platinum group metals.
Ruthenium is very rare so people are unlikely to come across any ruthenium compounds in normal day to day activities however they these chemicals are considered toxic to humans.

From Hydrogen to Tellurium - TECHNETIUM

2011-10-24T15:45:00.000-07:00

Technetium

The 43rd element is Technetium. It has the atomic symbol Tc. My knowledge of this element is very limited. In my research for this blog I discovered it it radioactive - a bye product of the radioactive decay of uranium. It has no biological role and is not found in nature. Apparently it was the first element to be synthesized. It was made by bombarding molybdenum with deuterium.

From Hydrogen to Tellurium - MOLYBDENUM

2011-10-16T13:33:00.000-07:00

Molybdenum

At position 42 is another transition metal - Molybdenum. It sits in the middle of the transition metals with Chromium above it and Tungsten below it. Molybdenum is known by the chemical symbol Mo. It has 4 electrons in its outer orbital and forms compounds with many other elements including hydrogen, fluorine, chlorine, oxygen, nitrogen and sulphur.

Molybdenum doesn't exist as elemental metal in nature but it can be isolated from its oxide. The isolated metal is a silvery white colour.

Small traces of Molybdenum are necessary for life in all species.

Because it doesn't expand or soften when heated to very high temperatures Molybdenum is used in applications that have to withstand very high temperatures. It is added to steel to increase the strength.

From Hydrogen to Tellurium - Niobium

2011-10-11T02:56:00.000-07:00

Niobium

Next in the series is Niobium - number 41. Scientists use the letters Nb for short. Another metal in the transition metals group, Niobium is a silvery, white, ductile metal with a bluish tinge.. Like many other metals, Niobium does not exist on its own in nature and although scientists found it in the early 1800s it wasn't until it was first extracted from minerals.

Chemically Niobium is very similar to Tantalum, the element that is beneath it in the periodic table. They are so similar that it is difficult to tell them apart.
Most of the Niobium we use today is produced in Brazil.

It is used mixed with other metals, particularly in steel to make it stronger. It is also used with other metals in super conducting magnets. Sometimes it is used in special commemorative coins.

It doesn't have a known biological role in humans, but as it isn't toxic it is sometimes used in jewellery and might be suitable for replacement body parts.

From Hydrogen to Tellurium - ZIRCONIUM

2011-10-04T08:39:00.000-07:00

Zirconium

Using the chemical symbol Zr, Zirconium is the 40th element. It is found in the second position of the second row of transition metals, below Titanium and above Hafnium. The reason scientists are interested in what lies above and below an element is because those elements that are above and below, although they have less or more electron shells, they all have the same number of electrons in their outer shells and it is this electron arrangement that contributes to the chemical behaviour. Hence elements in the same column have similar chemistry.It is not surprising therefore that Zirconium is a gray-white metal that looks like Titanium.

Interesting things about Zirconium are:

It is not found in its elemental state in nature - this means that you don't find lumps of Zirconium metal in the ground.

If you grind it up to make a powder and heat it up, it will burn spontaneously.

Though it has no known biological role, it is not thought to be poison.

It is found in some stars, lunar rock and some terrestrial rocks.

Some Zirconium containing minerals are used in jewellery.

Like titanium, Zirconium is sometimes used by doctors to replace worn out joints.

Yttrium

2011-09-26T02:25:00.000-07:00

Yttrium

The 39th element in the series is Yttrium. Yttrium is a transition metal. The transition metals sit in a block in the centre of the table. Yttrium appears in the first position of the second row. This tells us that it has 1 electron in its outer d-orbital.

Although it is never found in nature as a free element, when isolated it is a slivery metal. The surface layer reacts with oxygen giving a passivating layer so Yttrium is stable in air.
It has no role in biology and is thought to cause lung problems in humans.
It was discovered in the late 1700s near Yetterby in Sweeden hence the name -Yttrium.

Yttrium has some interesting uses. As it is very hard, a Yttrium aluminium compound is used to simulate diamond gemstones. Yttrium is also used to start the reaction in which ethene is polymerised to make polythene. When something is used to start a reaction but not used up in the reaction itself scientists call this material a catalyst so we would say that Yttrium catalyses the ethene polymerisation.

From Hydrogen to Tellurium - Strontium

2011-09-19T14:02:00.000-07:00

Strontium

Strontium is number 38 and has the chemical symbol Sr. In the same group as Magnesium and Calcium, Strontium is one of the Alkali Earth Metals. Strontium is very reactive with both water and air and therefore doesn't exist naturally in its elemental form. When isolated the metal is a silvery grey colour, however it reacts in air to give a yellowish coloured compound.

It was discovered in Scotland and it is named after the village - Strontian where it was discovered.

Students come across Strontium in their studies because when burned its salts give a characteristic red colour. This characteristic or trait also mean that it is commonly used in fireworks to give a red colour.

Below are links to a couple of video clips showing strontium salts burning with their characteristic red flame.
http://www.youtube.com/watch?v=vltFchuGi0Y

http://www.youtube.com/watch?v=BGd-bCpLDvE&feature=related

From Hydrogen to Tellurium - Rubidium

2011-09-12T14:16:00.000-07:00

Rubidium

For the 37th element, we jump back to the left hand side of the periodic table. Rubidium, with the chemical symbol Rb, is an Alkali Metal in the same group as Hydrogen, Lithium, Sodium and Potassium. What you. Should remember about these elements is that each of them have only one electron in their outer shell making them very reactive. In fact, rubidium is the most reactive we have met so far. The increase in reactivity is due to the distance of the outer electrons from the nucleus - the further away the electron is from the nucleus the less tightly the atom can hold onto the electron. Rubidium is very reactive in air and burns spontaneously in water.

Rubidium is a metal, solid at room temperature, but with a melting point of 40 degrees centigrade.

Rubidium is the 23rd most common element in the earth's crust. It is also present dissolved in sea water.

From Hydrogen to Tellurium - KRYPTON

2011-09-05T04:55:00.000-07:00

Krypton

Krypton is the chemical element with the atomic number 36 and the chemical symbol Kr. In the periodic table it is positioned at the end or right hand side of the fourth row, underneath Helium, Neon and Argon. This tells us that it has the right amount of electrons to fill its outer electron shell. We have already learned that elements with full outer electron shells are not reactive and Krypton is no exception. It is the next member of the inert gas family.

Maybe you knew Krypton was an element, maybe you didn't. It is a colourless, odourless, tasteless gas. It is found in very small amounts in the atmosphere. Neon and Argon are well knows for their ability to produce coloured light, red and blue respectively when an electrical current is passed through them. Krypton also has this property or trait but the light it produces is very bright white light.

Interestingly, Krypton has been used in defining the length of a meter. According to www.surveyhistory.org The French originated the meter in the 1790s as one/ten-millionth of the distance from the equator to the north pole along a meridian through Paris. It is realistically represented by the distance between two marks on an iron bar kept in Paris. The International Bureau of Weights and Measures, created in 1875, upgraded the bar to one made of 90 percent platinum/10 percent iridium alloy.

In 1960 the meter was redefined as 1,650,763.73 wavelengths of orange-red light, in a vacuum, produced by burning the element krypton (Kr-86). More recently (1984), the Geneva Conference on Weights and Measures has defined the meter as the distance light travels, in a vacuum, in 1/299,792,458 seconds with time measured by a cesium-133 atomic clock which emits pulses of radiation at very rapid, regular intervals.

None of the definitions changed the length of the meter, but merely allowed this length to be duplicated more precisely.

Fans of Superman will know that Krypton is a fictional planet, the native home of Superman. The story goes that the planet exploded, everyone was killed, except Superman, who was shot out from the exploding planet and ended up on earth.

Experiment of the week

Super strong paper

Given that Superman is so strong, it seems fitting to investigate the strength of paper this week.

You will need:

3 A4 sheets of 80g/m2 paper

3 empty spreadable butter containers or similar

a ruler

sand or small weights to load weight onto your bridge

a spoon

adult supervision

What to do

Position 2 of the butter containers 15 cm apart

Use the 3 sheets of paper to bridge the gap

Put the third empty container onto your bridge and slowly fill it with sand.

How much sand can you load onto the bridge before it collapses?

Who can make the strongest bridge?

Post your results and photos below

From Hydrogen to Tellurium - BROMINE

2011-08-30T09:28:00.000-07:00

Bromine

At number 35 is Bromine with the chemical symbol Br. Another non-metal, Bromine is the first element we have come across that is a liquid at room temperature. It is a red/brown liquid and when heated it boils to produce a red/brown gas at 60°C.

Bromine is in the same group as fluorine and chlorine and is therefore a halogen. Halogens are very reactive, they have space for one more electron in their outer electron shell and are very keen to fill that space by taking an electron from anything that will give them one. In terms of reactivity Bromine is less reactive than fluorine or chlorine but more reactive than iodine which in in the row below it in the table.

Bromine gas has a horrible smell. It is suffocating so not a good idea to have it around. Bromine liquid is corrosive to human tissue. The name Bromine comes from the Greek word Bromos which means stench.

Bromine is extracted from natural brine deposits taken from salt springs.

It is used as a dye, in pesticides and as a flame retardant in plastics.

From Hydrogen to Tellurium - SELENIUM

2011-08-30T04:06:00.000-07:00

Selenium

Selenium is the 34th element, a nonmetal, it has 2 allotropes - a purple/gray one and a red one, the purple/gray one being the most stable. Its chemical symbol is Se.

It is rarely found in nature but occurs as a compound in minerals.

The purple/gray allotrope is a semi conductor and it has an unusual property - it is a better conductor in the light than in the dark.

At number 34, Selenium has 34 electrons. This means that it has 2 spaces in its outer shell - just like oxygen and sulphur. Selenium forms similar compounds to sulphur - SeO2 and H2Se for example

Although it is extremely toxic in large doses, it is present at trace levels in humans and thought to be essential for the correct functioning of the body. We get our Selenium from eating plants and animals that contain Selenium. Brazil nuts have the highest concentration of any food. It is also contained in crab and lobster meat.

From Hydrogen to Tellurium - ARSENIC

2011-08-15T00:07:00.000-07:00

Arsenic

The 33rd element is Arsenic. This element I associate with all sorts of sinister things - murders, poisonings, mystery and intrigue. In Agatha Christie novels it was one of the main causes of death in her victims.
Toxic chemicals are labelled by scientists with the scull and crossbones to warn users to be especially careful with them, though it is recommended that chemists treat all chemicals as if they might be toxic to prevent any unwelcome surprises.

In terms of its properties or traits, Arsenic is a metalloid or semi metal, sitting in the periodic table between the metals and the non-metals. Arsenic occurs in a range of minerals as well as in its elemental form. In its elemental form it is usually a gray crystalline solid but like carbon and phosphorus, it has other allotropes. When heated it goes straight from a solid to a gas - we call this subliming.
Arsenic forms compounds with many other elements - oxygen, sulphur, etc
In the past arsenic compounds have been used as insesticides, weedkillers and wood preservatives. Thanks to the Elements exhibition in the Science Gallery I also learned that Arsenic compounds were also used by interior designers to give a green colour to wall papers.
A modern day use for Arsenic is in the computer industry where it is used for its semiconductor abilities.

From Hydrogen to Tellurium - GERMANIUM

2011-08-11T08:47:00.000-07:00

Germanium

Germanium, with 32 electrons, is the 32nd element in the table. During the week I came across this very colourful periodic table and have included it because it shows the different chemical groups in different colours. As you can see, Germanium is one of the semi metals often called metaloids. It is one that prior to this week I knew very little about.

Named after the country, Germany, Germanium was discovered in 1886 by a German chemist. It is obtained today by smelting zinc ores and from the burning of certain types of coal. It is the fifteenth most abundant element in the earth's crust.

Its main use is in the computer industry where it is used in semi conductors.

Interestingly, Germanium has a low toxicity in mammals but is highly toxic to some bacteria. Investigations are going on into its use as a means of killing bacteria or treating bacterial infections.

In some factories Germanium dioxide is used to help start the reaction used in the making of PET for drinks bottles.

From Hydrogen to Tellurium - GALLIUM

2011-08-06T13:52:00.000-07:00

Gallium

The 31st element, Gallium is an unusual material. It is not found in nature but can be extracted from minerals.

Gallium, which comes under Aluminium in the periodic table, is a metal. Most metals have high melting points but there are a few exceptions and Gallium is one of those exceptions. You might already know that Mercury, another metal, is liquid at room temperature. Gallium is normally solid at room temperature but it melts at 29 degrees centigrade. This means that its melting point is similar to that of chocolate and any of you who eat chocolate and especially those of you who came to Anyone 4 Science summer camps this year will know that you can melt chocolate in your hand. Well it is exactly the same for Gallium - hold a piece in your hand, which is at 37 degrees centigrade and it will melt! Fairly cool don't you think.

Because aluminium and Gallium look similar a chemistry trick is to make a teaspoon out or gallium instead of aluminium and offer this to your victim to stir their coffee, tea or hot chocolate. Guess what happens to their spoon? - It melts and goes to the bottom of the cup. Check out this disappearing spoon video - http://www.youtube.com/watch?v=QaJ_Yxj9bG8

Gallium also has a big range between its melting and its boiling temperature. This means it is suitable to use in a thermometer.

Another interesting property of Gallium is that is expands as it solidifies. It is unusual for this to happen as most materials contract as they cool. Another exception to this contracting as it cools rule is water. As water freezes it also expands. It is this property that causes pipes to burst when water freezes. If you stored Gallium in a glass container it would crack the container as it cooled.

Check out this cool video made by scientists at Nottingham University showing how to make Gallium beat like a heart. http://www.youtube.com/watch?v=N6ccRvKKwZQ&feature=player_embedded

Experiments of the Week

To show that water expands as it freezes

You will need:
Empty 500 ml PET bottle
water
measuring cylinder
marker

What to do:
Measure 400 mls water into the measuring cylinder and transfer it into the 500ml bottle.
Mark the line showing where the water comes to in the bottle.
Put the bottle of water in the freezer and leave overnight.
Take the bottle our of the freezer and mark the new level of the ice in the bottle.
Allow the liquid to melt.
Fill the bottle to the new mark.
Pour all the water into the measuring cylinder.
Calculate by how much the ice expands.

Experiment 2

Make your own Thermometer

You will need:
Glass bottle.
Water
Food colour
Drinking Straw
modelling clay / blu tack
cold water
basin with hot water

What to do:
Colour some cold water with a few drops of food dye.
Fill the glass bottle with coloured cold water.
Using the modeling clay fix the straw so that it is sealed into but sticking out of the bottle.
Stand the bottle in the basin of hot water

What happens? Leave your comments below.

From Hydrogen to Tellurium - Zinc

2011-08-05T15:10:00.000-07:00

Zinc

The last element in the first row of transition metals is Zinc. With an atomic number of 30, Zinc has 30 electrons. This means that Zinc has a full 4S orbital and also a full 3D orbital, but empty 4P orbitals and as a result of this Zinc is quite reactive and has lots of chemical similarities to Magnesium.

Zinc is a metal, not found in the elemental state but normally found in nature as Zinc Sulphide. Zinc metal is extracted from this mineral. We know that humans have known about Zinc for a long time because Zinc is combined with copper to give bronze which was used extensively in the bronze age. The Bronze age started about 3300BC and continued until 1200BC.

Zinc is a bluish white metal with a melting point of 419 degrees centigrade. Although this is very hot, it is much lower than the metals we have been considering over the last few weeks. The surface of the metal reacts quickly with air but the layer of oxide that is formed is unreactive and makes a layer which is difficult to penetrate.

This unreactive surface layer is widely used to help prevent oxidation of other metals. To prevent steel oxidising it is covered with a thin layer of Zinc. Zinc forms a tough exterior layer and prevents the steel from rusting.

Zinc is also used in batteries.

Zinc is an essential trace element for humans, plants and animals. We get zinc in our diets from red meats, beans, some nuts and seeds.

Other interesting facts about Zinc compounds include the following
It is used in sunscreens to prevent sun burn
It helps to prevent nappy rash in babies
It is used in toothpaste to prevent bad breath
It is used to kill germs - particularly bacteria and fungi

Experiment of the Week
Make your own battery

You will need:
a copper coin
a zinc nail
tissue paper
salt water
a volt meter or a 3V buzzer

What to do:
dip the tissue paper into the salt water
Make a sandwich - copper, soaked tissue, zinc
either connect the voltmeter to the 2 metals and record the voltage or complete the circuit using the buzzer with the red wire attached to the copper and the black wire attached to the zinc.

Post your results in the comments section below.

From Hydrogen to Tellurium - COPPER

2011-08-02T15:10:00.000-07:00

Copper

The 29th element is a well known element - Copper. Another metal, most children will be able to tell you that 1, 2 and 5 cent Euro coins are Copper.

This metal is a pinkish brown colour. When polished it is shiny but it reacts with air to give a dull oxide. We also associate a green colour with Copper. If you wear a Copper bracelet your will get a green deposit on it. Some churches have copper decorating their roofs. This Copper started out life as a shiny metal but over time, reacting with the air and pollutants in the air it has become green.

This is a photo of the church in Rathmines on the south side of Dublin. The green roof is made from Copper.

Copper has 29 electrons. They fill up the orbitals as follows: 1S 2, 2S 2, 2P 6, 3S 2, 3P 6, 4S 1, 3D 10. This means that the 3D orbital is full as a D orbital can fit 10 electrons. This is the first element we come across to have a full D orbital.

Copper is a good conductor of heat and of electricity. It is used in wires for carrying electricity.

Copper is also used in many of our homes for the plumbing. The copper pipes carry the water around the house. Where we live the water is slightly acidic as it comes through granite to get to our well. I can see the effects of this in our bathroom and in our hair. THe slightly acidic water travelling through the Copper pipes reacts with and dissolves some of the Copper. I see this as a green deposit in our shower tray and basins. It also shows up in the hair of blond family members - wash your blond hair in this Copper containing water and after a while your hair will have a green hue. This is especially visible on sunny days when the sun shines on the hair. What is causing the hair to appear green? The Copper from the pipes chelates or bonds to the hair.

Can you melt Copper? The answer is yes, but not in the flame of a candle which just doesn't get hot enough. Copper melts at 1084 degrees centigrade.

Copper isn't magnetic but an interesting experiment to do is to test the 1, 2 and 5 cent Euro coins to see if they are magnetic. What did you find? Can you explain this?

Experiment of the Week

Take Copper from a coin and deposit it on a nail.

You will need:

small cup or beaker

salt

vinegar

about 10 copper coins - dirty ones are fine

kitchen roll

nail

What to do:

Half fill a small beaker with vinegar (use approx 20 - 30 mls)

Add a teaspoon of salt.

Put your coins into the salt vinegar mix and leave for about 30 minutes.

Remove the coins and leave to dry on a piece of kitchen roll. Do not discard the liquid as you will need it for the next part of the experiment.

Dip a nail into the salt vinegar mixture and leave for about 10 minutes.

Remove the nail and examine it carefully.

What has happened?

Return to the coins. What has happened to them?

Explain your observations.

Leave your comments below.

From Hydrogen to Tellurium - NICKEL

2011-08-01T12:38:00.000-07:00

Nickel

Element 28 is Nickel which is another metal from the transition metal series. The name Nickel is familiar to many people, not because they know it as another element but because of the slang name given to the US 5 cent coin.

Although known as a Nickel, the 5 cent in fact is made of a mixture of 75% copper and 25% nickel. In spite of this it has the silvery colour of Nickel.

Like Iron and Cobalt, Nickel is magnetic, however the US Nickel is not magnetic as it doesn't contain enough Nickel to make it magnetic.

Nickel is used in stainless steel iron with 18% chromium and 8% Nickel.

Much "good" cutlery though referred to as silver isn't actually silver but nickel silver. Nickel silver is an alloy of copper, nickel and zinc. This same alloy is also used for making musical instruments and costume jewellery.

At the summer camps this year we have been looking at melting points. We found that sugar would melt at 186 degrees centigrade. Nickel also melts but at the much hotter temperature of 1455 degrees centigrade.

From Hydrogen to Tellurium - COBALT

2011-07-29T13:28:00.000-07:00

Cobalt

Though I got off to a good start, writing the blog each week , particularly during the busy weeks of the summer camps has proved more difficult that I thought. Now that there is a break in the camps for a few weeks hopefully I will get a chance to catch up.

Element number 27 is Cobalt. This element has 27 electrons and is another transition metal. Like many other elements Cobalt doesn't exist in nature in its elemental state but can be produced by smelting. Elemental Cobalt is a sliver, grey metal.

Again like the other transition metals, Cobalt forms compounds with many different elements and these compounds are varied in colour. One of the best known uses of a Cobalt compound is in cobalt blue, the dye that is used in pottery and glass to give a deep blue colour. There are many examples of this blue glass at the Elements Exhibition in the Science Gallery in Trinity. The exhibition opened 2 weeks ago and runs until mid September and is certainly worth a visit.

Cobalt is essential to all animals, including humans. It is found in vitamin B12. We need vitamin B12 to keep our brain and nervous system functioning properly and also for the production of blood. Vitamin B12 is found in fish, shellfish, meat - especially liver, poultry, eggs, dairy products and milk.

Cobalt chloride is known by leaving certificate students as a chemical used to test for the presence of water in desiccants. The anhydrous or dry version is blue and the hydrated version is pink. This colour change is reversible so if you dry pink cobalt chloride it reverts to its blue colour.

Another interesting fact about Cobalt is that it is magnetic.

From Hydrogen to Tellurium - IRON

2011-06-27T09:27:00.000-07:00

IRON

Most people are familiar with the 26th element - Iron. Its first claim to fame is from the Iron Age. This period of history extended from about 800BC to about 100BC. Prior to this we had had the Stone and then the Bronze age. The discovery of Iron led to great advances in civilization. Instead of having to mould tools, smiths were able to heat the iron and beat it into shape.

Though the 6th most common element in the universe, Iron is the most common element in the planet - most of the outer and inner core of the earth are made up of Iron. It is also essential for life. Haemoglobin in our blood is an iron containing molecule. A shortage of Iron in the human body leads to anemia. To prevent this Iron is added to some staple foodstuffs such as breakfast cereals.

So Iron has the chemical symbol Fe. Like manganese its symbol is made up of 2 sequential alphabetic letters, however Fe are sequential when you are saying the alphabet backwards.

Iron is very reactive - it reacts with oxygen to form rust. This rust then flakes off leaving the metal surface exposed so more rust formation occurs. Because Iron rusts so readily there are not many ancient pieces of iron from the Iron age still in existence.

Iron is mixed with Carbon to form steel. Steel is stronger than Iron.

Experiment of the Week

Extract Iron from Breakfast cereal.

You will need:
100g Cereal fortified with iron
A large ziploc bag
A magnet - it is a good idea to cover the magnet with sticky tape before doing this experiment as it is very difficult to remove the iron filings from the magnet when you have finished.
Magnifying glass

What to do:
Pour the cereal into the ziploc bag.
Put the magnet into the bag
Seal the bag
Shake the bag making sure the magnet moves around all the cereal.
Remove the magnet and examine it using a magnifying glass.

You should see little iron filings on the magnet.

From Hydrogen to Tellurium - Manganese

2011-06-24T14:03:00.000-07:00

Manganese

The first interesting thing I notice about this, the 25th element in the periodic table is that it is the only element in the periodic table whose chemical symbol consists of two sequential letters in the alphabet - Mn. Although Manganese, which is a metal does exist in nature it is not something I have ever knowingly come across. Most of my experience with Manganese is in the Manganese containing compound - Potassium Permanganate KMnO4

Potassium permanganate, which will cause purple stains if it comes in contact with your skin is often used in school and college chemistry experiments. I have only learned recently that it is also used to sterilise water and wounds and because of these properties and the fact that when mixed with ground up glucose tablets the friction causes it to ignite it is often included in survival kits.

Anyway to get back to the element itself........It is often used to prevent steel rusting.

Because Manganese compounds are often coloured they are used as pigments

From Hydrogen to Tellurium - CHROMIUM

2011-06-12T13:57:00.000-07:00

Chromium

Even before I understood the term metal, I had been introduced to Chromium, the 24th element in the periodic table. Polishing the Chromium bumper on my Dad's car is one of my early childhood memories, and very shiny it was too. It was much later when I learned that Chromium was used for this decorative purpose on cars because one of its properties is that it can be polished to give a very shiny appearance.

Our car was black, just like this one, with chrome plated bumpers, front grill, hubcaps, etc.

At number 24, Chromium has 24 electrons. It is known as Cr for short. Although most Chromium is extracted from minerals, there are some places in the world where it can be mined as Chromium metal.

Its name, Chromium, comes from the Greek word Chroma which means colour. It was given this name because Chromium combines with many different elements to give different coloured compounds. Over the years many of these Chromium compounds have been used to give paints their colours. Chromium compounds are not used so much for paint any more as people are worried about the effect these compounds have on our bodies.

My birthstone - the emerald, gets its green colour from the presence of Chromium atoms in it.

Rubies also get their red colour from the presence of Chromium atoms

Another use for Chromium is in the manufacture of stainless steel. On its own iron reacts with the oxygen in the atmosphere to form rusts. This means that untreated iron is not that useful. However if iron is mixed with Chromium the resulting alloy is stainless steel. This type of steel is enormously useful.

This week's challenge

Look around your house and see if you can find 10 places where you are using stainless steel. You can list them below or upload photos of them - maybe even your photo frame is made from stainless steel.....

From Hydrogen to Tellurium - VANADIUM

2011-06-10T03:28:00.000-07:00

Vanadium

The 23rd element is Vanadium. Scientists use the letter V for it. Vanadium is a metal, with 23 electrons. When it was first discovered scientists thought it was just another form of Chromium, the element we will be discussing next week.

According to jlab.org it was first discovered in South America and below is the interesting story about its discovery. It shows how difficult it was to get information and samples around the world in the 1800s.

Steve Gagnon writes - Vanadium was discovered by Andrés Manuel del Rio, a Mexican chemist, in 1801. Rio sent samples of vanadium ore and a letter describing his methods to the Institute de France in Paris, France, for analysis and confirmation. Unfortunately for Rio, his letter was lost in a shipwreck and the Institute only received his samples, which contained a brief note describing how much this new element, which Rio had named erythronium, resembled chromium. Rio withdrew his claim when he received a letter from Paris disputing his discovery. Vanadium was rediscovered by Nils Gabriel Sefstrôm, a Swedish chemist, in 1830 while analyzing samples of iron from a mine in Sweden. Check out http://education.jlab.org/itselemental/ele023.html for more information

Vanadium doesn't exist on its own in nature but is combined with other elements to form rocks and minerals.

It is a useful metal as it is corrosion resistant and strong. It is mixed with Iron to form an alloy which is used in axles, crankshafts and gears for cars, parts of jet engines, springs and tools

From Hydrogen to Tellurium - TITANIUM

2011-05-31T06:30:00.000-07:00

Titanium

The 22nd element is Titanium. It has 22 electrons and is given the chemical symbol Ti. Titanium is a metal in the transition metal series. Like many other elements we have discussed it is not found as an element in nature. It is present in many minerals.

An interesting metal, it is light, strong and very unreactive. This means that it is useful in a variety of tasks. It is used in the space and aviation industry - a light strong metal. It is used by doctors to make replacement bones and joints. It is especially useful as a joint replacement as it isn't magnetic and this means that doctors can still use MRIs on the patient to investigate other complaints.

The most commonly found compound of Titanium is the white powder, Titanium Dioxide TiO2. This is a whiter than white" material which also has many uses.

It is used in paint, sun screen, toothpaste and even to put the white m&m writing onto m&m sweets!

From Hydrogen to Tellurium - SCANDIUM

2011-05-22T06:05:00.000-07:00

Scandium

At number 21 with 21 electrons and the chemical symbol Sc is Scandium. It is the first in the group known to chemists as Transition Metals. The transition metals are placed in the gap we left in the previous rows between the second and third columns. So why have chemists grouped these elements together and what is different about them. As you know be now, scientists like to group similar things together. It might be objects of the same colour, objects of the same texture, but for chemists it is materials with the same chemical behaviour. The alkali metals from group 1, Lithium, Soduim and Potassium for example, all have one electron in their outer shell and use this electron to bond with other elements. The common trait of the transition metals is that they don't fill all the spaces in the lower energy shells before putting electrons into higher energy shells and this means that they use electrons from more than one shell or energy level to combine with other elements. I suppose you could say that they have rules of their own, maybe they are the teenagers of the periodic table! Because of this transition metal elements give share or bond with different numbers of electrons in different situations.

So what of Scandium? Well it is a metal, present in relatively small amounts in the universe. It doesn't exist in its elemental form in nature so has to be extracted from minerals by scientists. This extraction is difficult and was only done successfully for the first time in 1937. It had been discovered many years before by a Scandinavian chemist, Lars Nilson. Prior to Nilson finding it, this element had been predicted by Mendeleev, the chemist who first put forward the idea that the elements could be organised in a table - the periodic table of elements.

It is light and strong and forms alloys with aluminium that are sometimes used in the planes and bicycles.

Scandium is one of the elements that hasn't been studied a great deal, however researchers continue to explore its characteristics and chemistry so perhaps in the future we will have more interesting uses for it.

From Hydrogen to Tellurium - CALCIUM

2011-05-16T02:51:00.000-07:00

Calcium

Positioned next to Potassium and under Magnesium is Calcium. With the chemical symbol Ca and 20 electrons, Calcium is an element most children have heard about.

It is not naturally found in its elemental state - in other words you don't find lumps of calcium atoms on their own but when scientists remove the other elements leaving just Calcium they are left with a soft, grey / silver metal.

Calcium is grouped with Beryllium and Magnesium in the group known as the Alkali Earth Metals.

You may well have heard your parents encouraging you to drink milk, telling you that milk will give you strong teeth and bones. Milk is one of the foods that is rich in Calcium and Calcium is needed by the body. In fact our bodies are 5 per cent Calcium so for every 100g of our bodies 5 g are Calcium, and most of this Calcium is in our banes and teeth. It is the presence of Calcium in our bones that makes them opaque to x-rays. This characteristic is widely used to check to see if bones have been broken.

Calcium is also the fifth most abundant element in the earth's crust. Many rocks contain Calcium - limestone and chalk are both made from the Calcium containing compound Calcium Carbonate CaCO3. In caves, stalactites and stalagmites are Calcium containing compounds which have dissolved in water and moved through the rocks.

The mortar builders use to stick bricks together is a mixture of Calcium Hydroxide, known as lime, Sand and Water.

Cement is also made fromCalcium containing compounds.

Many Calcium containing compounds are not soluble in water but dissolve in other solvents such as acids. This means that buildings do not dissolve in rain but if you get acid rain which is caused by pollution then this acid rain can dissolve buildings. This can cause serious damage to old decorative buildings

Experiment of the Week
Dissolving egg shells

You will need
adult supervision
2 jam jars or jars with lids that seal
Water
Vinegar
2 eggs
Hot water
Basin containing cold water
bottle with a large neck such as the one in this picture -

What to do
Carefully place a raw egg into each of the 2 jam jars.
Cover one with water and put on the lid.
Cover the other with vinegar and put on the lid.
After 24 hours remove the lids and carefully pour off the liquids. Compare the 2 eggs. The one which was in the vinegar should be soft - its shell dissolved in the vinegar.
Fill the large necked bottle with hot water and then pour the water out.
Sit the rubbery egg on top of the bottle.
Cool the bottle by immersing it in the cold water.
Your egg should be sucked into the bottle.

From Hydrogen to Tellurium - POTASSIUM

2011-05-09T03:35:00.000-07:00

Potassium

Potassium, with the chemical symbol K, is number 19. Last week we discussed Argon, the inert gas, with its outer electron shell full. This means that Potassium with one extra electron must have three full shells and only one electron in its outer shell. The symbol K comes from the Kalium - the Latin name for this material.

We have talked previously about how elements with the same number of electrons in their outer shells behave similarly chemically and scientists who noticed this started to group the elements according to this. They represented these groups in a now famous diagram known as the periodic table of elements. This week as well as talking about Potassium I am going to introduce you to this famous diagram. Each week we will add our new Element of the Week. It will be shaded in blue and have a red outline.

All the elements we have already discussed are included. Any that are gases at room temperature I have shaded in green. The metals are silver, the solids red and the metalloids purple.

So what about our element of the week, Potassium? Well, it is in the alkali metal group with Sodium and Lithium. Like Sodium, it is very reactive - just mad to give away its outer electron. Lumps of Potassium aren't found in nature because it has long since given away its outer electron to form a compound with some other electron hungry species. Scientists have prepared pieces of Potassium but to keep it you have to store it in oil. It burns in the air giving a purple coloured flame. Check out this video to see what happens
http://www.youtube.com/watch?v=8HdAhs_-Y2g

It burns in water......check out this video...
http://www.youtube.com/watch?v=veR3gNXs8LQ&NR=1

Potassium containing compounds also give a purple flame when they are burned.

Although it is not found on its own, Potassium is very plentiful on the earth. It exists in many compounds. It is essential for both plant and animal like.
Plants absorb Potassium salts from the earth and if you burn a plant you are left with a substance we call potash - the ash of Potassium!
Farmers add Potassium fertilisers to their fields to help plant growth.

Potassium salts are also dissolved in the sea.

Potassium is essential for human life and each human body is 0.2% Potassium.
To calculate how much Potassium your body contains take your weight in kg and multiply by 0.002. If you weigh 40 kg for example, 80g of that is Potassium! We get Potassium from fruit, nuts and vegetables with potatoes, bananas and dried apricots often being mentioned as good sources.

In our bodies we use Potassium to help our brains work properly, to help our muscles work well and to keep our fluid levels balanced.

People who are concerned about eating too much Sodium in their diets, but like their food to taste salty often use LoSalt. LoSalt is a mixture of Sodium Chloride (table salt) and Potassium Chloride.

Experiment of the Week:
Work out how much potassium your body contains

You will need:
Weighing scales
Calculator or pen and paper

What you do:
Weigh yourself.
Multiply your weight by 0.002

The answer is the amount of your body that is Potassium!

From Hydrogen to Tellurium - ARGON

2011-05-02T14:18:00.000-07:00

Argon

Argon with the chemical symbol Ar is number 18. It is located on the periodic table in the third row of the right hand column underneath Helium and Neon. Like Helium and Neon, Argon is a member of the inert or noble gas family. This means that it is a gas at room temperature and that it is a very stable material that does not react with other elements, or itself for that matter.

Previously we have talked about the fact that air is a mixture of gases - mostly Nitrogen (78 parts of every 100) and oxygen (21 parts of every 100). Of the remaining 1 part a large amount of that is Argon.

At number 18, Argon has 2 electrons in its inner shell and 8 in each of the 2nd and 3rd shells. This means that all 3 electron shells are full. It is these full electron shells which make Argon so stable - it is neither looking for additional electrons to fill up the last few spaces nor looking to give away a few electrons to empty the outer shell.

The name Argon comes from the Greek word for lazy - very appropriate for an element which just won't react!

I was asked recently why the inner electron shell only has 2 electrons and the 2nd and 3rd 8. Well this is because in close to the nucleus the inner shell is very small and can only fit 2 electrons. The 2nd and 3rd shells are bigger and can fit 8 each. When we move on to the next row we will see that the 4th shell is considerably bigger and can fit an extra 10 electrons.

I was also asked about the position of the columns and the gaps in the first 3 rows. Well the elements are grouped in columns along with other elements with similar chemical behaviour. Helium behaves similarly to Neon and Argon so is placed in that group - it is in the group with full outer shells, not the group with 2 electrons in the outer shell.

So what is Argon used for? Well the main use is in situations when you want to prevent other reactions taking place so Argon is used for welding. It is also sometimes used as a preservative and also as a fire extinguisher.

Like Neon it becomes coloured when an electrical current is passed through it so it is used to make blue/purple advertising signs.

From Hydrogen to Tellurium - CHLORINE

2011-04-25T13:59:00.000-07:00

Chlorine

The seventeenth element is Chlorine. It has 17 electrons, 2 in the inner shell, 8 in the 2nd and 7 in the third, thus leaving one space in the outer shell to completely fill it. Elements with one space in their outer shells are grouped in the Halogen family. This is the second halogen we have met, Fluorine being the first.

Chlorine is a green coloured gas which was first isolated in the 1770s. The gas is poisonous. It also has a bleaching effect, taking the colour out of things it comes in contact with. The gas is not found in nature as Chlorine is very reactive and combines with other elements to give compounds.

Most people are familiar with the smell of Chlorine - it is used in very small quantities in our drinking water and also in swimming pools to kill bacteria.

One of the compounds, Sodium Chloride, is used regularly in our kitchens - we refer to it as salt. It seems hard to believe that if the gaseous molecules of Chlorine combine with the metal atoms of sodium that a white crystalline solid which we know as salt results.

From Hydrogen to Tellurium - SULPHUR

2011-04-17T14:06:00.000-07:00

Sulphur

The sixteenth element, Sulphur is given the symbol S. This element is found in its elemental form, often near volcanos and springs. It is a yellow crystalline solid, composed of rings of 8 Sulphur atoms.

It has been known about since ancient times and is the material referred to as "brimstone" in the bible.

Sulphur is a non-metal which sits under oxygen in the periodic table. Like oxygen if forms compounds with 2 other atoms -chemists say it is divalent. An example of a divalent compound of Sulphur is Hydrogen Sulphide - H2S. Hydrogen Sulphide is a colourless, poisonous gas that smells like rotten eggs.

It can also form molecules with different number of bonds. An example is Sulphur Dioxide, SO2 where it is joined by double bonds to both oxygens. Sulphur dioxide is sometimes used to preserve fruit for jam making.

Sulphur dioxide is produced when coal is burned. This SO2 reacts with water H2O in the atmosphere to form Sulphuric Acid H2SO4. This then falls as acid rain and affects crop growth and damages buildings.

In fact Sulphur forms compounds with all elements except the noble gases.

If you heat Sulphur with iron you get a new compound - iron sulphide. This experiment is often used to show the difference between a chemical mixture and a reaction producing a new material. Before heating this mixture the iron could be separated from the Sulphur using a magnet. Once it has been heated and reacted the new compound is not magnetic, nor can the magnet separate the iron from the Sulphur.

Many Sulphur containing compounds are smelly. You might be familiar with the sulphury smell from car's catalytic converters. Garlic and the Skunk also owe their smell to Sulphur containing compounds.

Experiment of the week
To examine the effect of Acid Rain on crops

You will need:
4 clear plastic tubs with lids (3kg Margarine containers are ideal.)
Kitchen roll
Pea seeds
Water
Vinegar
spoon

What to do:
Soak the peas overnight in water
In each of the 4 tubs cover the bottom with a few layers of kitchen roll. Dampen the kitchen roll well with water
Sprinkle pea seeds on the damp kitchen roll.
Label the containers 1,2 3 and 4
Put the lid onto container 1 and leave in a warm place
To container 2 add 1 spoon of vinegar. Put on the lid and leave alongside container 1.
To container 3 add 2 spoons of vinegar. Put on the lid and leave alongside container 1.
To container 4 add 3 spoons of vinegar. Put on the lid and leave alongside container 1.

Examine each day for the next 2 weeks and record your results.

Which set of peas will grow best?

From Hydrogen to Tellurium - PHOSPHORUS

2011-04-11T15:46:00.000-07:00

Phosphorus

At number 15 and with the chemical symbol P, we find Phosphorus. In the periodic table Phosphorus sits below Nitrogen. Like Nitrogen, Phosphorus has 3 electrons in its outer shell and therefore reacts similarly to nitrogen.
It is a non-metal and like many other elements it is not found as an element in nature.
Elemental Phosphorus forms many different crystal structures and each structure has its own colour. White, Red and Violet Phosphorus are 3 such forms. We found previously that carbon exists in a number of different forms and that the different carbon allotropes look and feel very different. This is also the case for Phosphorus.

Different allotropes of Phosphorus

Phosphorus was discovered by a German alchemist when he was trying to turn urine into gold. Instead of gold he ended up with a white material which glowed in the dark and when lit, burned very brightly.

Because Phosphorus can glow in the dark it is often used on the faces of watches so you can tell the time in the dark.

Because it can burn so well, it is used on the rough part of match boxes that is used to strike matches on.

Phosphorus is essential for both animal and plant life. DNA contains Phosphorus as do many plant fertilisers. It is also found in washing powder

From Hydrogen to Tellurium - SILICON

2011-04-04T14:00:00.000-07:00

Silicon

At number 14 is the unusual element Silicon with the chemical symbol Si. Why do I say it is any more unusual than the others? Well with its 4 outer shell electrons, it sits in the periodic table just under Carbon. We already learned that carbon is a non-metal. We have also learned that the elements with the same number of outer shell electrons behave similarly. When it comes to Silicon however this is not quite true. Silicon has some properties of a metal and some of a non-metal posing problems for scientists as to which group it should be in. In the end they decided it should go into a group called metaloids - a material with some metal and some non-metal characteristics. We also found out a few weeks ago that Boron has this same part metal, part non-metal behaviour.

This nearly metal behaviour is what makes Silicon interesting and very important to our lives today. It is known as a semiconductor because it doesn't conduct electricity as well as a metal but it is better at conducting than a non-metal. Semiconductors are widely used in the electronics and computer industries.

So what is it like? Well, Silicon is grey with a metallic appearance. It is very plentiful in the universe, but is hardly ever found as elemental Silicon. Instead it is found combined with oxygen as silica, SiO2. Sand is made of silica and this sand is in turn used to make glass. Small bags of Silica are also often found packed with shoes or in new handbags. The job of these little packets is to absord water so the leather products don't get damp.

Pure crystalline Silicon dioxide resonates at a certain frequency and because of this property it is used in watches.

Silicon combines with carbon oxygen and hydrogen to make a series of polymers known as silicones. You might have come across such rubbery polymers - the wristbands which were very popular a few years ago were made from silicone..

From Hydrogen to Tellurium - ALUMINIUM

2011-03-29T00:42:00.000-07:00

Aluminium

In the 13th spot we have an element that is familiar to most of us - Aluminium, with its chemical symbol Al. And you have guessed it, Aluminium has 13 electrons - 2 in the inner shell, 8 in the middle one and 3 in the outer. To fill the outer shell you know by now that it needs another 5 electrons but Aluminium normally forms compounds with 3 bonds, just pairing up its outer electrons.

So what does it look like? Well Aluminium is a silvery white metal. It is light and non-magnetic. It is very plentiful in the earth's crust but is not needed by either plants or animals for life. As far as we know it is not bad for you or poisonous but there are some people who think it might not be good for you. There is more research going on to find out more about this.

Although it is plentiful in the earth's crust it isn't found as lumps of Aluminium metal but as part of various minerals. Scientists extract the Aluminium from there minerals to get the material we know so well.

We use it for lots of things. One of the important uses children know about is in drink cans. Have you noticed that they are made from a different material than baked bean tins? It is also used in window frames, in cars, engines and in some countries they use it for their coins.

There have been times in history when Aluminium was considered to be very valuable, more valuable even than gold, and in those days it was used to make jewellery.

It costs a lot of money and uses a lot of energy to extract Aluminium from the earth so these days we recycle our Aluminium. For every €100 it would cost to extract Aluminium from the earth we can recycle the same amount for €5 so it is a very good idea to do this - saving money and energy.

Experiment of the week: The Magic Tilting Can

You will need:

One empty 330ml drink can

Water

What to do:

Tilt the can over and see if it will balance on the rim at the bottom edge. You should find that it tips over and won't balance.

Pour about 100 mls of water into the can and try again carefully tilting the can right onto the rim.

It balances!

How does this happen? Post your explanations and photos below.

Chemistry from Hydrogen to Tellurium - MAGNESIUM

2011-03-21T02:11:00.000-07:00

Magnesium

At number 12 we have Magnesium with the chemical symbol Mg. Magnesium is a silvery white metal.

Magnesium is very plentiful in the universe and on earth, however like many of the other elements we have discussed, it is never found as an element on its own.
As we all know the sea is salty. This saltiness comes from various salts including Sodium Chloride the salt we are all familiar with and Magnesium Chloride which is a salt of Magnesium.

To be healthy, our bodies need Magnesium. Our bones and teeth contain Magnesium and we also need it to help digest or get energy from our foods.
The following foods are some of the sources of Magnesium - Cereals, soybean, green leafy vegetables, almonds, seeds, nuts, apples, lemon, grapefruit, seafoods, meat, milk and dairy products.

Magnesium has 12 electrons, 2 in the inner shell, 8 in the next shell and 2 in the outer shell. Again the outer shell has room for 8 so Magnesium is happy to give away these 2 "extra" electrons and form compounds with elements whose outer shells need one or two electrons to be full. You might remember way back near the start of the year we met another element with 2 electrons in its outer shell? Remember Beryllium?. It also has 2. Scientists discovered that beryllium and Magnesium behave similarly so they grouped them into a family called the Alkali Earth Metals.

Perhaps you can also remember the names of some elements whose outer shells need one or two more electrons to be full? These elements react and form compounds with the Alkali Earth Metals.

Remember oxygen? It needs 2 electrons so one oxygen combines comfortably with one Magnesium to give magnesium oxide, MgO. The reaction in which Magnesium and oxygen combine is interesting. To combine them you need to get a long thin piece of magnesium and light it. It will burn with a very bright white flame which is so bright you could damage your eyes if you look directly at it. If you were to try to use a large sheet or lump of Magnesium you would find it impossible to get it to light, even using a blow torch. Scientists have discovered that this is because Magnesium is a very good conductor of heat. No sooner than you have you heated up one corner, it has cooled itself down by passing the heat to other parts of the piece of metal. There are very interesting video clips of this. Check this one out http://boingboing.net/2010/01/23/saturday-morning-sci-13.html
We saw last week how sodium combines with 1 chlorine atom to make sodium chloride. Magnesium also forms a chloride but it needs 2 chlorine atoms as each one only has room for 1 of the two electrons magnesium has to give away.

There is a story about a farmer who was giving his cattle a drink of water. No matter what he did they refused to drink. He found however that when he washed their cuts and grazes with the same water they healed very quickly. Further investigation showed that the water had dissolved in it a Magnesium compound - magnesium sulphate MgSO4. This chemical is known as Epsom Salts and is still used by farmers on animals skins and by people in their baths to make their skin feel soft. Epsom salt makes nice needle shaped crystals and this week's experiment describes how to grow them.

Experiment

You will need:
epsom salts, water, beaker, warm water, shallow tray, spoon, ruler, adult supervision.

What to do:
Before you start examine the Epsom salt crystals carefully. Measure them, note their shape. You might even stick a few into your copy.
Place 1 or 2 spoons of Epsom salts into a beaker. Add warm water, one spoon at a time. Stir well after each spoon of water is added. Continue until all the Epsom salt has dissolved. If you did the experiment last week you should notice that you need much less water to dissolve the Epsom Aalto than you did to dissolve the sodium chloride.
Pour the solution into the shallow tray and leave in a warm dry place. After a day or 2 your crystals should begin to grow. What shape are they? How long? You should have long needle crystals varying in length from 1 to 10 cms.

From Hydrogen to Tellurium - SODIUM

2011-03-14T15:36:00.000-07:00

Sodium

The eleventh element in the periodic table is Sodium. The chemical symbol for Sodium differs from the symbols for all the elements we have met so far. H is the symbol for Hydrogen, He for Helium, Li for Lithium and so on. So who can guess the symbol for Sodium? Well, that is a tricky one. I'll give you a clue. None of the letters found in the word Sodium are used in the chemical symbol. That still leaves a possible 20 letters and there might be more than one letter in the name so you probably still can't guess. What is Sodium called in other languages? In Latin it is called Natrium, in Arabic Natrun so maybe now you can have a guess - Na of course.

So what about Sodium (Na) and its electrons? It has one more than Neon which we talked about last week. We also found out that Neons outer electron shell was full so this means that Sodium has an extra shell and there is only one electron in this extra shell.

Sodium

One electron in the outer shell, does that remind you of any other elements? Hydrogen and Lithium are in the same situation. Scientists noticed this and also that elements with one electron in their outer shells behave similarly to each other and are therefore grouped into a family. We call this family the Alkali Metals.

The alkali metals are very reactive. Sodium is so reactive it has to be kept in oil to stop it reacting with the oxygen in the air. Put it in water and you get all sorts of hissing, spitting and even flames.

Sodium is a shiny grey metal. It is soft and can be cut easily with a knife.

Sodium is happy to give away its outer single electron so it forms compounds with other elements that need one electron to complete their outer shell. One such element is chlorine. All of you are familiar with the compound that Sodium makes with chlorine, we call it salt or sodium chloride and add it to our food to make it tastier.

Experiment: Grow sodium chloride crystals

You will need:
Salt
Glass
Spoon
Measuring jug
Hot water
Adult supervision
A flat dish or tray

What you do:
Take a dessert spoon of salt. Put it into a glass. Add about 100mls hot water taking care not to get burned. Stir carefully until all the salt has dissolved or for about 5 minutes. If the salt hasn't all dissolved add a few more mls of hot water and stir again. Continue until all the salt has dissolved.
Pour the solution into a flat dish or tray and leave in a warm place.
As the water evaporates the salt crystals should grow. They will be cubic crystals.

What to expect:

Chemistry from Hydrogen to Tellurium - NEON

2011-03-06T13:06:00.001-08:00

Neon

Week 10 and it is the turn of the tenth element on the table. This element is called Neon and given the chemical symbol Ne. It has 10 electrons in total, 2 filling the inner shell and the other 8 filling the outer electron shell. This full electron shell makes Neon very stable and un-reactive. Because of the un-reactive nature of elements with full outer shells they are in a family called inert gases or noble gases. If you look INERT up in the thesaurus the synonyms will give you a good idea of the behaviour of Neon and its other family members.

Neon atoms exist on their own and are caller monoatomic. These atoms are small and lighter than air. This means that a balloon filled with Neon, like a helium filled balloon, would float in air. Neon is fairly rare on earth but is the fifth most abundant element in the universe.

Neon is well known for its use in signs. When the Neon gas, which is normally colourless is electrified it gives a characteristic red/orange glow.

Tubes, containing Neon gas which can be electrified, are moulded into shapes and used in high streets to advertise various products. Though these types of lights are all called Neon lights, no matter what colour they are, however, only the red ones actually contain Neon. The purple light in this image contains another gas from the inert gas family called Xenon.

Chemistry from Hydrogen to Tellurium - FLUORINE

2011-03-01T13:48:00.000-08:00

Fluorine

The 9th element in the atomic series is Fluorine. It has 9 electrons and is given the chemical symbol F. With 9 electrons, Fluorine is very anxious to find another electrons so it's outer electron shell is full. You could describe Fluorine as being very hungry for another electron. This hunger for another electron makes Fluorine the most reactive of all the elements.

When scientists discovered the way electrons were arranged in shells in the different elements and also that different elements had different numbers of electrons, they also noticed that elements with the same number of electrons in their outer shells had similar behaviours. They then gave family names to elements with similar behaviours. Fluorine is the first member of the Halogen family.

The name Fluorine comes from the Latin word Fluo which means stream or flow of water. Fluorine was given that name because scientists noticed that Fluorine helped molten metal to flow. Molecules with Fluorine are not good at sticking to other molecules. Scientists have used this non-sticky behaviour to create a Fluorine containing molecule called Teflon. Teflon is the black slippy material used on the surface of frying pans to stop sausages and other things sticking to the pan.

Many of you will have heard about Fluoride. Fluoride is the name given to a fluorine atom which has an extra electron. Fluoride is present in very small quantities in toothpaste to help prevent tooth decay. While a small amount helps prevent tooth decay, larger amounts are bad for you and can make dark marks on teeth and cause other problems. This is why you should use only a pea sized piece of toothpaste on your toothbrush and spit out the toothpaste instead of swallowing it.

Chemistry from Hydrogen to Tellurium - OXYGEN

2011-02-21T02:37:00.000-08:00

Oxygen

Number 8 on the periodic table of elements is Oxygen with the chemical symbol O. Oxygen is a clourless gas with no smell. Most people have heard of it because it is essential for life. Oxygen is produced by plants in a process called photosynthesis. Photosynthesis means making something using light. When light shines on plants and there is water and carbon dioxide present the plants absorb the water and carbon dioxide and convert it into glucose and Oxygen. The Oxygen is then released into the air and as we saw last week when discussing nitrogen, air is 21% Oxygen. This means that if you had 100 "air atoms", 21 of them would be Oxygen.

Being number 8 on the periodic table means that Oxygen has 8 electrons, 2 in the inner shell and 6 in the outer one. More important is the fact that it has space for 2 more electrons in that outer shell to make it full. This means that Oxygen is keen to borrow or share 2 electrons with other atoms. Because of this need for extra electrons, Oxygen atoms are not found on their own, but instead joined in pairs, in much the same way as hydrogen which we discussed in week 1.

O2 molecule.

You will also be familiar with another Oxygen containing compound - Water. Water, or H2O is made up of 1 Oxygen atom and 2 hydrogens.

As well as people and animals not being able to live without Oxygen, fire cannot burn without it either. This is why when you remove the Oxygen from a fire by covering the fire with a fire blanket, the fire goes out.

Experiment to remove oxygen from the air.

You will need adult supervision / help, a breakfast bowl, a nightlight, water, matches or a lighter and a drinking glass

Put about 1 cm of water into the breakfast bowl.

Float the candle on the water.

Light the candle.

Place the upturned drinking glass over the candle.

After a few seconds the flame will go out. The air trapped in the drinking glass has had its oxygen removed.

Look at what happens to the water. Can you explain this?

Chemistry from Hydrogen to Tellurium - NITROGEN

2011-02-13T02:53:00.001-08:00

Nitrogen

The 7th element in the atomic series is Nitrogen with the chemical symbol N. Though not much talked about, Nitrogen is one of the elements we come in contact with every day. Most people think of air as being oxygen because it is the oxygen in the air that we need to breath and live. However if you got 100 "atoms" of air, 78 of them would be Nitrogen and only 21 oxygen.

So what do scientists know about Nitrogen?. Well at number 7 in the series it has 7 electrons. This means 2 in the inner shell or orbital, 2 in the second s shell and one in each of the 3 p orbitals, so nitrogen looks like this:

You might like to make a model of a Nitrogen atom. All you need is 6 balloons, 2 of each of 3 colours. Inflate them and tie them together. The picture of 3 pairs of balloons tied together give a much better idea of the shape of a Nitrogen atom than my drawing.

Nitrogen, with its 5 electrons in the outer shells has space for 3 more electrons. Because of this Nitrogen atoms are never found on their own. Two Nitrogen atoms join together and each shares the 3 electrons in the p orbitals with the other. Scientists write this as N2. Sharing 3 electrons means they there is a triple bond between the 2 Nitrogen atoms.

So what is Nitrogen like? Well, as we know from air, at room temperature, it is a colourless, tasteless, gas. It has no smell. It is non-metalic. When cooled to -195.8°C it becomes a liquid. This liquid, known as Liquid Nitrogen is often used to cool reactions. When cooled in liquid Nitrogen, bananas become very hard and brittle and can be smashed into pieces if hit by a hammer.

Nitrogen is present in all living things. Plants are about 4% Nitrogen. Humans are about 3% Nitrogen. DNA and proteins are Nitrogen containing compounds. Plants with the help of special bacteria take nitrogen from the air and convert it into fertiliser.

So next time you breathe in, don't forget to give a little thought to this week's element of the week - Nitrogen.

Chemistry from Hydrogen to Tellurium - Carbon

2011-02-07T02:27:00.000-08:00

Carbon

The sixth element on the periodic table is Carbon. By now you can probably guess how many electrons it has. Yes, you are right - it has 6. And its chemical symbol is C.

Carbon is one of the most interesting elements known to scientists. It forms so many different compounds with other elements that there is a subdivision of chemistry called Organic Chemistry which is the study Carbon containing compounds. Organic chemists study the shape of Carbon containing molecules, their properties or traits, how to make them and their reactions with other chemicals.

The outer electron shell of Carbon has space for 8 electrons. Carbon has 2 electrons in its inner shell which leaves 4 in the outer shell. This means there are 4 spaces in the outer shell so each carbon atoms likes to bond or share electrons with 4 other atoms.

All of you will be familiar with Carbon and most of you use it every day. In recent weeks the elements we have been discussing don't exist on their own in nature and scientists have to extract them from other materials. Carbon is different. Carbon is a non-metal. Not only does it exist in nature, it can exist in different forms depending on how the atoms are arranged.

In one form the Carbon molecules bond to 4 other Carbons with each atom as far from the next as possible. This gives a tetrahedral shape for 4 atoms and a 3 dimensional series of tetrahedra all joined together when there are lots of atoms.

This form of Carbon is a clear, very hard crystal with lots of faces which reflect light and make it sparkle. We call this material Diamond.

The same Carbon molecules can also join together to form sheets of atoms. The atoms make a sheet of hexagonal rings and there are occasional links between 2 sheets to give a 3 dimensional structure.

In this form Carbon is a black and very soft. We call this material Graphite. Graphite is used as the nibs or "lead" in pencils. Years ago real lead was used but it was found to be poisinous and was replaced by graphite. So the next time you write with pencil remember that you are rubbing layers of Carbon atoms from the nib onto your page!

Coal, soot and charcoal are also made from Carbon. In these cases the atoms are not arranged in such a regular structure

In 1985 another allotrope or arrangement of Carbon atoms was discovered. It is similar to graphite but it consists of a combination of 5 and 6 atom rings. The 5 atom rings mean that the structure isn't flat so shapes like footballs and tubes can be formed. These are called Fullerenes.

Chemistry from Hydrogen to Tellurium - BORON

2011-01-28T06:56:00.001-08:00

Boron

The 5^th element in the periodic table is Boron and has the chemical symbol B.

By now you will probably have noticed that each element we discuss is slightly bigger that the last. We started with Hydrogen, Atomic Number 1 and 1 electron, through Helium with 2 electrons, Lithium with 3, Beryllium with 4 and now Boron with 5.

Don’t know if you remember but Hydrogen and Helium were both gases and extremely light.

Lithium and Beryllium are both metals and solid. When describing something as a solid, liquid or a gas, scientists would always add some information about the temperature. This is because if you heat a solid you can turn it into a liquid and if you keep heating, the liquid will become a gas. This happens at different temperatures for different materials.

You will all be familiar with water – in Ireland it is a liquid, but if you lived in the North Pole you would be more used to seeing water as a solid! So the correct way to describe Lithium and Beryllium is say they are solids at room temperature. Room temperature is not a very precise term. It is the temperature that a room is at when people are comfortable in it. This is usually between 20°C and 25°C.

So what about Boron – well firstly, like Beryllium it doesn’t exist on its own. Scientists can separate it from other molecules but it is never found in nature as a clump of Boron atoms.

Almost all the elements in the periodic table can be grouped or classified as either metals or non-metals. Hydrogen and Helium are non-metals, Lithium and Beryllium metals but Boron is different. It is classified as a Metalloid. This means that it is in “no man’s land” – chemically it is somewhere in between. So sometimes it behaves like a metal and other times like a non-metal.

So far when I have drawn atoms I have always shown the nucleus in the middle with the electrons orbiting in circles around the nucleus – a bit like Saturn and its rings. Boron’s fifth electron can’t fit into the outer circular orbital as it already containing 2 electrons so is now full. The next empty orbital isn’t circular like the previous ones but it is the same shape as the number 8.

Boron Molecule

Although elemental boron is not found, boron is present in many chemical compounds. It has 3 electrons available for bonding and it usually forms the sharing, covalent type of bonds. An example of such a compound would be BF₃ – Boron triFluoride. Fluoride needs one extra electron to fill its outer electron shell so three fluoride atoms link up with one boron to make a stable compound.

It is borosilicate glass which gives pyrex its ability to be put into hot ovens without the glass shattering. Boron compounds are used in bullet proof vests and boron is also used in the computer industry to change the properties of semiconductors. Boron is found in borax, Na₂B₄O₇, which in the past was used as a cleaner.

Borax Molecule

Today and among children in particular, borax’s claim to fame is that it is the cross linking agent used to transform PVA glue into Slime.

Check out the following cool activity using the boron containing compound, Borax:

You will need: Borax, water, PVA glue, 2 beakers, weighing scales, spatula or spoon

Step 1 Dissolve 5g borax in 100mls warm water.

Step 2 To 50g PVA glue add 150mls water. Mix well. (The quantity of water required depends on how thick the PVA is so you might need to adjust the amount of water needed).

Step 3 While stirring the PVA solution gradually add small amounts – say 1 teaspoon at a time, of the borax solution you prepared in step 1. Continue stirring and adding borax solution until the PVA turns to a rubbery slime.

Step 4 Take the slime out of the container and have fun playing with it.

Chemistry from Hydrogen to Tellurium - BERYLLIUM

2011-01-24T02:24:00.000-08:00

Beryllium

Here we are at week four and the turn of Beryllium, with its chemical symbol Be. What a nice name - I love the sound of it - so exotic. When it was first discovered, because of its sweetness it was called Glucinum - a name which came from glucose. Tasting chemicals is a really bad idea - in the past lots of chemists have died as a result of tasting and even working carelessly with chemicals which turned out to be poisonous. Beryllium is no exception - its salts are toxic and should never be tasted.

The name Beryllium came from the Beryl, the mineral name of a range of gemstones which contain Beryllium and include Emeralds and Aquamarine. Beryl is a molecule made up of Beryllium, Aluminium, Silicon and Oxygen atoms

Emerald Aquamarine

Aquamarine is a relatively common gemstone and is said to be the birth stone for March.

Emerald is quite rare and therefore a valuable gemstone. It is the birth stone for May.

If any of you have earrings, rings or bracelets with aquamarine or emeralds in them then you have a few Beryllium atoms!

Beryllium is quite rare. It doesn't exist naturally on its own but when scientists separate it from Beryl it is a strong gray metal. Because Beryllium metal doesn't get much bigger or smaller when it is heated or cooled it is ideal for using on planes and rockets.

Beryllium is number 4 on the periodic table and has 4 electrons orbiting its nucleus. These 2 pairs of 2 electrons make it quite happy so it is not a reactive element. It does sometimes give away its outer 2 electrons to atoms of elements such as chlorine which are very keen to fill up their outer electron shell.

From Hydrogen to Tellurium - LITHIUM

2011-01-10T08:32:00.001-08:00

Lithium

Lithium is the third element on the periodic table. It is not as famous as either hydrogen or helium so you might not have heard of it before. Being the third element, it has 3 electrons, 2 in the inner circle and one on its own in an outer orbit.

Lithium is quite happy to give away this outer electron and because of this scientists say that it is reactive. It gives away its outer electron to elements such as Hydrogen which need one additional electron to fill their outer shell of electrons. When a Lithium atom gives an electron to a hydrogen atom a new compound called Lithium Hydride is formed. There is no sharing of electrons involved. Scientists call this type of bonding ionic bonding.

I think of Lithium as being like a family with 3 children (electrons). The younger 2 are happy to stay near their parents (the nucleus). The older child or electron likes to go on sleepovers and often stays away for long periods of time.

The bonds in this type of compound are different to those discussed when we were talking about hydrogen joining with another hydrogen atom to make H2. In H2 both hydrogen atoms share the 2 electrons. Scientists call this a covalent bond.

The covalent bonds of Hydrogen remind me of 2 families with one child each living next door to each other. The children play together, moving from house to house, garden to garden. It is almost as if both families have 2 children.

Other elements which need one extra electron are Fluorine and Chlorine and these also form ionic bonds with lithium. We will be talking about these elements during weeks 9 and 17 respectively.

So what is Lithium like? Well, it is a metal and a solid, but unlike most metals it is very light - it is so light it can float on water. However if you put it on to water it will start to react - it will dart around and bubbles of hydrogen will be formed. As well as being very light it is soft and can be cut with strong scissors.

And its uses - the most common use for Lithium is in batteries.