Which of the following ions came from an atom that gained 2 electrons? a. 0^2- b. li+ c. mg^3+ d. n^3-

Group 6 elements like Oxygen like to take on the extra two electrons to become a 2- anion and take on the noble gas configuration. so the O^2-, which looks like O=O, will have two oxygens sharing two electrons answer is O^2-

answer: c.

explanation:

there are two significant figures.