Final answer:
The charge that results when oxygen becomes an ion is -2, as it typically gains two electrons to reach a stable electron configuration, resulting in an oxide ion with a negative charge.
Step-by-step explanation:
When oxygen becomes an ion, it typically gains two electrons to achieve a full outer shell, similar to the noble gas configuration of neon.
This gain of electrons results in a negatively charged ion known as an oxide ion. The charge of an oxygen ion is -2. Therefore, the correct answer to which charge results when oxygen becomes an ion is (d) -2.
Oxygen atoms, according to the octet rule, seek to fill or share their outer shell electrons to achieve a stable configuration.
The valency of oxygen is 2, which means it commonly forms bonds with other elements by gaining two electrons, hence its typical oxidation state and ion charge is -2.