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Calcium [Ca]
CAS-ID: 7440-70-2
An: 20 N: 20
Am: 40.078 g/mol
Group No: 2
Group Name: Alkaline earth metal
Block: s-block  Period: 4
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 1757K (1484°C)
Melting Point: 1115K (842°C)
Density: 1.55g/cm3
Discovery Information
Who: Sir Humphrey Davy
When: 1808
Where: England
Name Origin
Latin: calx, calcis (lime).
 "Calcium" in different languages.
Sources
Obtained from minerals like chalk, limestone and marble. Very abundant. Makes up 3.5% of crust (making it the fifth most abundant element). Occurs only in compounds. Calcium is found mostly in soil systems as limestone, gypsum (CaSO4 - 2H2O) and fluorite (CaF2). Stalagmites and stalactites contain calcium carbonate (CaCO3).
Annual production is around 112 million tons.
Abundance
 Universe: 70 ppm (by weight)
 Sun: 70 ppm (by weight)
 Carbonaceous meteorite: 11000 ppm
 Earth's Crust: 41000 ppm
 Seawater: 390 ppm
 Human:
   1.4 x 107 ppb by weight
   2.2 x 106 ppb by atoms
Uses
Used for dehydrating oils, decarburization and desulfurization of iron and its alloys, getter in vacuum tubes. Also used as an alloying agent for aluminium, copper and lead, a reducing agent for beryllium and used in fertilizer, concrete and plaster of paris.
Calcium is an important component of a healthy diet. Calcium is an essential component shells, bones, teeth and plant structures.
History
Calcium was prepared as lime by the Romans under the name calyx in the 1st century A.D., but the metal was not discovered until 1808. Berzelius and Pontin prepared calcium amalgam by electrolizing lime in mercury. Davy was then successful in isolating the impure metal. Why did it take so long? Calcium is the fifth most abundant metallic element in the earth's crust, but is never found in the elemental form because it is so reactive. It is found in limestone (CaCO3) gypsum (CaSO4.2H2O) and fluorite (CaF2).
Notes
Calcium is an important component of a healthy diet. A deficit can affect bone and teeth formation, while over retention can cause kidney stones. Vitamin D is needed to absorb calcium. Dairy products, such as milk and cheese, are a well-known source of calcium.
Hazards
Pure calcium is a shiny soft metal that will react violently with water to release hydrogen and calcium hydroxide. Skin contact may cause burns.
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