Friday, July 29, 2011

From Hydrogen to Tellurium - COBALT

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.