Question

13. Would you expect oxygen to form a cation or anion? How many electrons would it gain or lose? Why?

Answer 1

Answer: C)Anion, it would gain 2 electrons to satisfy the octet rule.

Explanation:

Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.

The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration of oxygen with 8 electrons is

$O:8:1s^22s^22p^4$

The cation is formed by loss of electrons and anions are formed by gain of electrons.  

In order to complete its octet and get stable, it gains 2 electrons and thus would form an anion.

$O^{2-}:10:1s^22s^22p^6$