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: