What Are Anions?
Ions consist of either atoms or groups of atoms that have a charge — either negative or positive. If they have have gained electrons, they will be negatively charged, due to having more electrons than protons, and are called anions. An anion is usually composed from more than one atom. These are called polyatomic ions and are usually built around a core atom, which in most cases is a non-metal. Common anions include acetate, bromide, hydroxide, carbonate, chlorate, chloride, chromate, cyanide, fluoride, nitride, nitrate, sulphite, phosphate and oxide. Except for hydroxide and cyanide, all anions that end in –ide are monatomic. Group 17 atoms called halides, which include such elements as fluorine, chlorine, bromine and iodine, form anions with their charge of negative one. Elements such as oxygen and sulfur carry a charge of negative two, while nitrogen and phosphorus carry a negative three charge. All of these combine with an atom to form an anion. Most polyatomic ions combine with o
