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Calcium is a soft alkaline earth metal known since ancient Roman times.

Name Calcium
Atomic Number 20
Atomic Weight 40.078 u
Symbol Ca
Melting Point ( °C ) 1115 K
Boiling Point ( °C ) 1757 K
Density (g/cm3) 1.55
Earth crust (%) 5%
Discovery (Year) 1808
Group 2
Electron configuration [Ar] 4s2
Ionization energy (eV) 589.622 KJ/ml

Other useful information:

Period= 4, Abundance: Earth- 7.72 log, Solar 4.79log, Source: Calcite (oxide), State of Matter: Solid , alkaline earth metal, Atomic Radius: 197 pm, Ionic Radius: 114 pm, Electronegativity: .9 unities, number of Isotopes: 6, Common Oxidation Numbers:+2 ,


Water: reacts slowly, Air: reacts fast, Acids: highly reactive, Bases: no reaction,


Calcium was known since ancient Roman times but it was not isolated until 1808 by Sir Humphry Davy in The United Kingdom


Calcium is used in mostly in clinical research and nutritional studies

Interesting facts:

Every human contains 1 kg of calcium in their body, calcium is the main component of the bone, some foods contain calcium, a gram of the element cost 0.48 $/100g or depending on it purity, its a conductor of electricity, Calcium is not radioactive,

Resources :


<ref>http://education.jlab.org/itselemental/ele020.html</ref> <ref>http://www.webelements.com/calcium/isotopes.html</ref>