An ion is an atom or a group of atoms that carries an electric charge because it has either lost or gained electrons.
- If an atom loses electrons, it has more protons than electrons and becomes a positively charged ion, called a cation.
- If an atom gains electrons, it has more electrons than protons and becomes a negatively charged ion, called an anion.
Ions are very important in chemistry and everyday life. They are present in salts, acids, bases, and even in our bodies, where they help in nerve impulses and muscle contractions.