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Atomic Number	20

Atomic Symbol	Ca

Atomic Weight	40.078 amu

Group	Alkaline Earth, 2

Form	Solid

Density @ STP	1.54 g/cm³

Melting Point	842 °C (1547.6 °F, 1115.2 °K)

Boiling Point	1484 °C (2703.2 °F, 1757.2 °K)

Heat of Fusion	8.54 kJ/mol

Heat of Vaporization	155 kJ/mol

First Ionization Potential	6.11316 eV

Electronegativity (on Pauling scale	1.00

Specific Heat Capacity	0.647 J/g K

Ground State Electron Configuration	4s²

Oxidation State(s)	+2

Stable Isotopes and Natural Abundance on Earth	⁴⁰Ca, 96.941%; ⁴²Ca, 0.647%; ⁴³Ca, 0.135%; ⁴⁴Ca, 2.086%; ⁴⁶Ca, 0.0004%; ⁴⁸Ca, 0.187%

Selected Radioisotopes	⁴⁵Ca; ⁴⁷Ca

Atomic Radius	194 pm

Crystal Structure	Cubic

Discovered by	Davy, 1808