Periodic Table of WIS

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