Calcium

Atomic number

20

Atomic mass (u)

40.08

Category

Alkaline earth metal

Standard state

Solid

Melting point

841.85 °C (1115 K)

Boiling point

1483.85 °C (1757 K)

Density (g/cm³)

1.54

Electronegativity (Pauling)

1

Electron configuration

[Ar]4s2

Oxidation states

+2

Atomic radius (pm)

231

First ionization energy (eV)

6.113

Discovery & recognition

Discovery year / period (PubChem)

Ancient

Discovery credited to (RSC)

Humphry Davy

Date or period recorded by RSC

1808

Discovery place

Known since antiquity; no single first-discovery place is established.

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Calcium is the fifth most abundant metal in the Earth’s crust (4.1%).”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.