An oxygen atom has eight protons and a hydrogen atom has one proton, How many electrons are in a hydroxide ion?

A. 8

B. 9

C. 10

D. none

The answer is C.

Explanation:

When hydrogen react with oxygen to form hydroxide ion, the electron in each element will add up together.

So 8-electrons of oxygen react with 1-electron of hygrogen to form 10-electrons of hydroxide.

In an element, atomic number (proton number) is equal to numbet of electrons.

I believe the answer is c