# Is an ion an atom that has a net positive or negative electric charge?

I write species, because compound ions, i.e. $N {O}_{3}^{-}$, $N {H}_{4}^{+}$, $S {O}_{4}^{2 -}$, as well as $N {a}^{+}$ or $C {l}^{-}$ manifestly exist.
As you know, in aqueous solution even $N {a}^{+}$ would not be a naked cation, but of the form ${\left[N a {\left(O {H}_{2}\right)}_{6}\right]}^{+}$, the aquated ion, a coordination complex if you like. That is why we write $N {a}^{+} \left(a q\right)$ as a shorthand.