Relative atomic mass: 40.078 +- 0.004

English: Calcium
French: Calcium
Croatian: Kalcij
German: Calcium
Italian: Calcio
Spanish: Calcio

Atomic number: 20
Group numbers: 2
Period: 4
Standard state (20 oC): solid

Discovery: 1808 Sir Humphry Davy (GB)
Calcium was discovered by Sir Humphry Davy (GB) in 1808. The origin of the name comes from the Latin word calx meaning lime. It is a fairly hard, silvery-white metal. Exposed surfaces form oxides and nitrides. Calcium reacts with water and oxygen. It only occurs in compounds. Calcium is obtained from minerals like chalk, limestone and marble. Pure metal is produced by replacing the calcium in lime (CaCO3) with aluminium in hot, low pressure retorts. Calcium is used by many forms of life to make shells and bones, as a pure metal it has little use, however two of its compounds, lime (CaO) and gypsum (CaSO4), are in great demand by a number of industries. The price of 99.8 % pure calcium granules is 126.90 for 1000 g.
Electronic configuration: [Ar] 4s2
Formal oxidation number: +2
Atomic radius: 197.4 pm

Electronegativities: 1
Thermal conductivity: 190 W/(m K)
Electrical resistivity (20 oC): 3.91 microOhm cm

Melting point: 842 oC
Boiling point: 1484 oC

Heat of fusion: 9.33 kJ/mol
Heat of vaporization: 150.6 kJ/mol
Heat of atomization: 177.74 kJ/mol

19K <= 20Ca => 21Sc

ASCII Periodic Table of the Elements
6 Jan. 2020
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