Do formal charges represent actual separation of charges?
Not so much. The best way to see how a charge really exist on a molecule is to look at an electron density map which is calculated by quantum mechanics. You’ll see how arbitrary our charge system is. The charge system is used for bookkeeping purposes, which means, we know there is a total of say +1 charge on this molecule so we’ll write it on the Nitrogen. Look at these molecules’ electron density map that I have below. Benzene doesn’t have a formal charge, but you can see in the map there are more electrons around the ring than at the sides. Acetone doesn’t have a formal charge but there is a huge electron density at the oxygen and a lack of density at the carbonyl carbon. Acetate has a formal charge but look at how it is delocalized.
