# How do you calculate formal charge of an ion?

Most of the time when we write a chemical formula, we write it in such a way that the constituent atoms are neutral. This is not always the case, but most of the time we are understood. We could write common salt as $N {a}^{+} C {l}^{-}$ but more commonly it appears as $N a C l$. More complicated and relevant examples appear in the links and elsewhere.