Answer: -2 because it gains 2 electrons
Step-by-step explanation:
An ion is considered to be an atom which is formed by gain or loss of electrons.
The ions are classified into two which are called the cation and anion.
The cation is classified as the positive charge formed by loss of electrons.
The anion is classified as the negative charge ion formed by gain of electrons.
On gaining two electrons, the atom would occupy -2 charge.