How to understand chemical reactions as you learn them

The OCP Core Carbonyl Chemistry is good.

HI, I'm having trouble with constructing equations. Would you be able to explain why the symbol equation for Sodium reacting with Oxygen is = Na+02 -> Na20 ?

Does this have to do with the crossover rule?

Na forms the ion: Na⁺
O forms the ion: O^2-

Due to the crossover rule, you need 2 sodium ions to balance out the charges so that the overall charge of the compound is 0.


I believe the equation would be:
4Na + O₂ --> 2Na₂O ?

Ah, so that is why we use the crossover rule. I've forgotten the basics

It's gcse C1

I remember being taught the crossover rule but it was never explained. Thank you!

No worries!

I'm so sick of memorising all this ****ing jibberish is there any way I can actually understand it?

For example

Reactions of carbonyls in a2

No worries!

You're right to make sure that they has a full outer shell, but they're ions in Na₂O! An oxygen atom has 6 electrons in its outer shell, so the anion is O^2- and has 8 (i.e. a full shell). A sodium atom has 1 electron in its outer shell, so its ion is Na⁺

You need to make sure the charges cancel out so your overall compound is neutral which is why its Na₂O

If I was to write the formulae for lead phosphate how would I know whether it should be Pb2+ or Pb4+?

It gets complicated that far down the periodic table! The full electron shell rule doesn't work so well. It's Pb²⁺ but I'd have thought you'd be told that.