What is true about a positively charged ion?
it is formed when an atom loses electrons.
it is usually a nonmetallic element.
it has more electrons than protons.
it is formed when an atom gains protons.

The answer you're looking for is

It is formed when an atom loses electrons.

Explanation ??

Well, the electrons are the negative part of an atom right? And protons are the positive part of the atom! We learned that when all of us were younger and first learning about atoms. The main reason it isn't "It is formed when an atom gains protons" is because most atoms have protons, it can still be negative as long as it has more electrons than protons. So that leaves us with, "It is formed when an atom loses electrons." I believe this is correct because since it is losing electrons, it is losing the negativity!

(( Max ))