Question

How do you calculate formal charge of an atom?

Answer 1

The formal charge is the difference between `Z`, the atomic number of the atom, and the number of electrons, bonding and non-bonding, that surround that atom.

Explanation:

Our conception of formal charge goes back to the old idea that in a covalent bond, the electrons are shared. Where there is a lone pair, for instance on `N` or `O`, the charge devolve solely to that atom,

See this old answer, and [also here.](https://socratic.org/questions/what-is-the-charge-on-a-carbonate-ion-co-3-2-compared-to-the-number-of-protons-h)