Answer
An ion is an atom that gains or loses an electron such that it has a positive or negative charge.
A cation is an atom that has lost electrons and therefore has a positive charge.
An anion is an atom that has gained electrons and therefore has a negative charge.
Work Step by Step
Recall that an element is defined by its number of protons, and this remains unchanged. It's the gain or loss of electrons that can give an atom its charge.
