Question

When an oxygen atom forms an ion, it gains two electrons
What is the electrical charge of the oxygen ion?

A.
-1

B.
-2

C.
+1

D.
+2

Answer 1

Note the atom of the Oxygen is electrically neutral, meaning it has equal numbers of electrons and protons.

So if it gains 2 electrons, it would have excess of 2 electrons, hence its charge would be -2.

Option B.

Answer 2

The electrical charge of the oxygen ion is -2.