• Question: what is not supposed to react with gold that you use in your job?

    Asked by Gymnast16 to Andrew on 25 Jun 2015.
    • Photo: Andrew Fensham-Smith

      Andrew Fensham-Smith answered on 25 Jun 2015:

      So might have to have a bit of background – atoms are made up of the core nucleus, which is positively charged (the number of protons in this gives what element it is). The nucleus is surrounded by negatively charged particles called electrons. With that said…

      So there are things in chemistry we call “oxidants”. An oxidant is something which is really good at ripping electrons (which are a type of particle) away from things. An example of an oxidant is… oxygen! So in the reaction of say, magnesium with oxygen you would turn a neutral magnesium atom into a magnesium(2+) ion and give those two electrons to an oxygen atom to make an oxygen(2-) ion. In this, you would say that the oxygen had oxidised the magnesium, which just means the magnesium has given some electrons to the oxygen. Make sense?

      So gold doesn’t like being oxidised – it likes to hold onto its electrons really tightly, which is why we almost always find gold in it’s unoxidised state – as gold metal. It is so hard to take electrons from gold you have to use really harsh and horrible acids (like one called aqua regia – which is latin for kings water). My project involves trying to get gold to react with chemicals called oxidants and give up electrons.

      There are lots of different types of oxidants, which I won’t bore you by listing, but gold doesn’t react with all of them. In my project, I try and put atoms near the gold which kind of make it uncomfortable, and want to give up electrons more easily.

      It’s really difficult to really describe what I’m doing, but I hope this helps!