2012: Advent Chemistry: Sodium Chloride

by on December 8, 2012

Ionic bonds are really simple. Where covalent bonds are about sharing electrons, in an ionic bond one atom completely loses an electron to the other. The first atom become positively charged, because it’s got more protons than electrons now. The second becomes negatively charged, because it’s got more electrons than protons. And since they’ve got opposite charges, they stick together, just like magnets.

Sodium chloride, common salt, is a perfect example of this. Chlorine is very electronegative and sodium is actually electropositive – it wants to give up the electrons it has, not gain more. Sharing electrons doesn’t suit either of them, because it doesn’t get them to a nice, neat, properly paired off set of electrons in their orbitals. So sodium loses its outermost electron to chlorine. Both atoms become ions, which is what you call an atom with a whole electron more or less than normal, and the ions stick together like glue.

You can’t split sodium chloride up into just one of each ion. The ions form into huge lattices, like marbles stacked together, all held together by magnetic attraction.

I think that’s brilliant.

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