Symbol

Ca

Atomic Number

20

Atomic Mass

40.08

Family

Group 2 (Iia) Alkaline Earth Metal Pronunciation

CAL-cee-um

Overview

Calcium is an alkaline earth metal. The alkaline earth metals make up Group 2 (IIA) of the periodic table, a chart that shows how the elements are related. They include beryllium, magnesium, strontium, barium, and radium. The alkaline earth metals are more chemically active than most metals. Only the alkali metals in Group I (IA) are more reactive.

Calcium compounds are common and abundant in the Earth's crust. Humans have used calcium compounds for hundreds of years in construction, sculpture, and roads.

Calcium metal was not prepared in a pure form until 1808 when English chemist Humphry Davy (1778-1829) passed an electric current through molten (melted) calcium chloride.

Metallic calcium has relatively few uses. However, calcium compounds are well known and widely used. They include chalk, gypsum, Limestone, marble, and plaster of paris.

Discovery and Naming