Question

What is the ion notation for an atom with 8 protons and 10 electrons?

Answer 1

This is an oxide ion with a negative two charge.

Explanation:

With eight protons, we are necessarily looking at oxygen, but with 10 electrons, the net charge on the ion is minus two.
This charge is written as a superscript in the upper right corner relative to the symbol for oxygen atoms

Closest I can get to the write the symbol in this answer is `O^2-` (the - sign should be part of the superscript).