Atomic number 20
Name Calcium
Atomic mass 40.078(4)
Electronic configuration [Ar] 4s2
Electronegativity 1
Atomic radius 174 pm
Ion radius 100 (+2) pm
Van der Waals radius pm
Ionization energy 590 kJ/mol
Electron affinity -2 kJ/mol
Oxidation states 2
Standard physical state solid
Bonding type metallic
Melting point 1115 °C
Boiling point 1757 °C
Density 1.55 g/cm³
Type alkaline earth metal
Year discovered Ancient