From Hydrogen to Tellurium - ALUMINIUM

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

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

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

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

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.