Summary:
- Anion is negative ions that are formed when a nonmetal atom gains one or more electrons.
- Anions are so named because they are attracted to the anode (positive field) in an electric field.
- Iodide ion is widely used in water supplies to help prevent tooth decay.
- Chloride is an important component in ion balance in blood and is needed by the thyroid gland to make the hormone thyroxine.
- The charge on the anion is indicated by a superscript following the symbol.
- Common anions are listed in the Table below.