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

1 Answer
Nov 3, 2016

An ion is a species that has net positive or negative electric charge.

Explanation:

I write species, because compound ions, i.e. #NO_3^-#, #NH_4^+#, #SO_4^(2-)#, as well as #Na^+# or #Cl^-# manifestly exist.

As you know, in aqueous solution even #Na^+# would not be a naked cation, but of the form #[Na(OH_2)_6]^+#, the aquated ion, a coordination complex if you like. That is why we write #Na^+(aq)# as a shorthand.