Ion   An atom or molecule that has acquired an electrical charge by either gaining or losing electrons. A cation is an ion that has lost electrons and acquired a positive charge. An anion is an ion that has gained electrons and acquired a negative charge.

Used in the following modules: Absorption, Distribution and Storage of Chemicals, Acids and Bases, Atomic Theory II, Cells, Chemical Bonding, Chemical Reactions, Earth's Atmosphere, Matter: States of Matter, Minerals III, The Carbon Cycle, The Nitrogen Cycle, Water