oxygen atoms tend to gain 2 electrons to form oxide anions. (a) what is the charge on a oxide anion…

Explanation:

Step1: Recall electron - charge relationship

Each electron has a charge of - 1.

Step2: Calculate oxide - anion charge

Since oxygen gains 2 electrons, the charge is $(-1)\times2=- 2$.

Step3: Recall oxygen atomic - mass value

The average atomic mass of an oxygen atom is approximately 16 atomic mass units.

Answer:

(a) - 2 (b) 16