(From the
Latin calx, "
lime") A soft, silver-white,
metallic chemical element, one of the
alkaline-earth metals, found in
limestone,
marble,
chalk, etc., always in combination. It is used as a
reducing agent, and is the essential part of
bones,
shells, and
teeth.
Symbol: Ca
Atomic number: 20
Atomic weight: 40.078
Density (at room temperature and pressure): 1.55 g/cc
Melting point: 842°C
Boiling point: 1,484°C
Valence: +2
Ground state electron configuration: [Ar]4s2