Flexi Says: Atoms cannot only gain extra electrons. They can also lose electrons. In either case, they become ions. Ions are atoms that have a positive or negative charge because they have unequal numbers of protons and electrons. If atoms lose electrons, they become positive ions or cations. If atoms gain electrons, they become negative ions or anions. Like fluoride, other negative ions usually have names ending in –ide. Positive ions, on the other hand, are just given the element name followed by the word ion. For example, when a sodium atom loses an electron, it becomes a positive sodium ion. The charge of an ion is indicated by a plus (+) or minus sign (-), which is written to the right of and just above the ion’s chemical symbol. For example, the fluoride ion is represented by the symbol F-, and the sodium ion is represented by the symbol Na+. Anions are so named because they are attracted to the anode (positive field) while cations are attracted towards the cathode (negative field) in an electric field.