20

Ca

Calcium
40.078 (4)
 Historical Information

Compounds such as lime (CaO, calcium oxide) were prepared by the Romans in the first century under the name calx. Literature dating back to about 975 AD notes that plaster of paris (calcium sulphate, CaSO4, dehydrated gypsum) is useful for setting broken bones.

Basic Information Shells
  • Name:Calcium
  • Symbol: Ca
  • Atomic number: 20
  • Atomic weight:40.078 (4)
  • Standard state: solid at 298 K
  • Group in periodic table: 20
  • Group name:Alkaline earth metal
  • Period in periodic table: 4
  • Block in periodic table: s-block
  • Classification: Metallic
 calcium
Uses Trivia
  • the solubility of the carbonate in water containing carbon dioxide results in stalactites and stalagmites (Cheddar Gorge) and hardness in water.

Calcium as the element is a grey silvery metal. The metal is rather hard. Calcium is an essential constituent of leaves, bones, teeth, and shells. Calcium is the fifth most abundant element in the earth's crust and makes up more than 3% of the crust.