Anion , atom or group of atoms carrying a negative electric charge. See An anion has more electrons in its atomic orbitals than it has protons in its atomic nucleus. The opposite of an anion is a cation, which has a positive charge. The name " anion " comes from the words anode and ion. In an electrochemical cell, anions are attracted to the positively charged anode. Anions are atoms or groups of atoms that have gained one or more electrons, resulting in a negative electrical charge. An anion is an atom or molecule that has gained one or more electrons, giving it an overall negative electrical charge. The key difference lies in how they are formed and their resulting charge: an anion forms by gaining electrons (becoming negative), while a cation is formed by losing electrons (becoming positive).
