An atom that has fewer neutrons than protons and more electrons than protons is a(n)
ion.

The right answer is Negative (anion).

Anion is an ion that, having gained one or more electron (s), carries one or more negative electric charge (s), (since the number of negative charge (electrons) is greater than the number of charges positive (protons)): for example, the Cl- chloride ion is the chlorine atom that has gained an electron. Conversely, a cation contains fewer electrons than protons.

It is so called because during an electrolysis, this ion is attracted by the positive electrode called anode, in the same way that the poles of opposite charges of the magnets attract.