Lithium, a member of the alkali metals, has three protons, three electrons and four neutrons. It has an atomic weight of 6.941 atomic mass units and is a solid at room temperature.
Li is the abbreviation for lithium, and its name comes from "lithos," the Greek word for stone. Lithium has a high specific heat, allowing it to be used to make unique glasses and ceramics. It can also be combined with other elements, such as copper, aluminum, manganese and cadmium, to make lightweight metals that are used to manufacture aircraft. Lithium is combined with carbonate to form a drug that is used to treat manic depressive disorder.