Calcium

Alkaline earth metal · 40.08 u · group 2, period 4

Calcium · Ca

Atomic number20

SymbolCa

CategoryAlkaline earth metal

Standard stateSolid

Group · Period · Block2 · 4 · s

Electron configuration[Ar]4s2

Atomic mass40.08 u

Atomic radius231 pm

Protons / Neutrons / Electrons20 / 20 / 20

Shells (e⁻ per shell)2, 8, 8, 2

Electronegativity (Pauling)1

Ionization energy6.113 eV

Electron affinity—

Oxidation states+2

Melting point1.12e+3 K · 841.9 °C

Boiling point1.76e+3 K · 1.48e+3 °C

Density1.54 g/cm³

Year discoveredAncient

CPK color

#3DFF00

State at room temp (25 °C)

solid

Position