Calcium
Symbol: Ca
Atomic Number: 20
Average Atomic Mass: 40.078
Group number: 2
Group name: Alkaline earth metal
Period number: 4
Here is a brief description of calcium.
Standard state: solid at 298 K
Colour: silvery white
Classification: Metallic
Availability:
This sample is from The Elements Collection, an attractive and safely packaged collection of the 92 naturally occurring elements that is available for sale.
Calcium is a metallic element, fifth in abundance in the earth's crust, of which it forms more than 3%. It is an essential constituent of leaves, bones, teeth, and shells.
The metal is a silvery colour and is rather hard. Chemically it is one of the alkaline earth elements; it readily forms a white coating of nitride in air, reacts with water, burns with a yellow-red flame, forming largely the nitride.
Calcium does not occur free in nature. Calcium is found mostly as limestone, gypsum and fluorite. Stalagmites and stalactites contain calcium carbonate.
Isolation
Here is a brief summary of the isolation of calcium.
Calcium metal is readily available commercially and there is no need to make it in the laboratory. Commercially it can be made by the electrolysis of molten calcium chloride, CaCl2.