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Calcium Ca
Where is calcium used--or where does it impact our everyday lives?
Present in bones as calcium phosphate, Ca3(PO4)2
Calcium is a dietary requirement
Calcium is a reactive element that readily reacts with water producing hydrogen gas and the alkali calcium hydroxide, Ca(OH)2
Calcium
Symbol: Ca
Soft solid, gray alkaline-earth metal at room temperature
Melting Point: 842 oC
Boiling Point: 1,484 oC
Density: 1.54 g/mL
Discovered by Sir Humphry Davy in 1808. He named calcium after the word calx, which is what the Romans called lime.
Calcium is readily found throughout the Earth’s crust, mostly in the form of rocks and minerals, but it is never found free in nature because it easily forms compounds by reacting with water and oxygen. Examples of minerals in which it’s found are limestone, calcium carbonate, CaCO3, dolomite, calcium magnesium carbonate, and gypsum, calcium sulfate, CaSO4. It is the 5th most abundant element in the Earth's crust.
Uses of calcium: Calcium can be found in bones and teeth, in shells (clams, oysters and other animals in the sea), cement and nerves and muscles.
Reactivity with water and air: 2Ca + O2 --> 2CaO
Calcium takes a long time to burn with oxygen, but then it bursts into an intense white flame with a bit of red at the end.
Calcium nitride may form small amounts in air: 3Ca + N2 --> Ca3N2
Calcium forms calcium hydroxide and hydrogen gas with water: Ca + 2H2O --> Ca(OH)2 + H2
Electron Configuration:
2,8,8,2 1s2, 2s2 2p6, 3s2 3p6, 4s2
Common Compound calcium carbonate (CaCO3).
LANL.gov
Image right and above id a compound of calcium viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip in October 2015
--a transparent calcite crystal of calcium carbonate, CaCO3, shows double-image refraction because it disrupts the view of images behind it--see the word calcite.
WIS Photographer
A sample of andradite, Ca3Fe2(SiO4)3 from Ojos Espanoles mine, Cardenas, Mexico viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip
WIS Photographer
Pre-treated roads in winter can have a liquid layer of deicer applied depending on the road temperature and the type of pecipitation expected. Magnesium chloride and calcium chloride treatments are more effective than sodium chloride (more ions per mole! NaCl versus MgCl2 and CaCl2. The temperature should be above -7 dec C (20 deg F).
Calcium is present in this sample of aragonite, CaCO3. Many rocks are metal carbonates. This sample is from Agrigento, Sicilia, Italy viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip
WIS Photographer
Calcium is a dietary supplement
Calcium is present in the mineral stokesite with albite CaSnSi3O9.2H2O from Galileia, Minas Gerais, Brazil viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip
The element calcium is found in fluorite , CaF2, the mineral form of calcium fluoride, on display at the National Museum of Natural History in Washington D.C. This halide mineral came from the Ozark Mahoning mine, Rosiclare, Illinois, USA and contains calcium which exists pure as a light gray metallic solid with the atomic number 20. Calcium is an alkaline earth metal in Group 2 of the Periodic Table and because it is so reactive it is not found as a free element in nature but in many minerals including limestone, CaCO3. China and Mexico supply the majority of the world’s fluorite.
Photographed by Ryha E