Metal

An opaque lustrous elemental chemical substance that is a good conductor of heat and electricity and, when polished, a good reflector of light. Most elemental metals are malleable, ductile, and are generally denser than the other elemental substances. Metals are structurally distinguished from nonmetals by their atomic bonding and electron availability. The electron band structure of metals is characterized by a partially filled valence band. The "free electrons" lost from the outer shells of metallic atoms are available to carry an electric current. The defining property of a metal is that it is an element with a positive thermal coefficient of resistivity, meaning the electrical resistivity of a metal continuously increases as temperature increases. About 80% of the known chemical elements are metals.

See also: Intermetallic, Refractory, Transition Metal, Virgin Metal.