20
Ca
Calcium
Alkaline earth metal period 4 group 2 s-block discovered: Ancient
As a chemical element
Properties of the atom — they do not depend on what substance it is part of.
- Atomic number
- 20
- Atomic mass
- 40.08 a.m.u.
- Electron configuration
- [Ar]4s2
- Electronegativity
- 1 on the Pauling scale
- Atomic radius
- 231 pm
- Ionization energy
- 6.113 eV
- Oxidation states
- +2
As a simple substance
Properties of the substance these atoms form under ordinary conditions.
- State at 25 °C
- Solid
- Melting point
- 1115 K (841,85 °C)
- Boiling point
- 1757 K (1 483,85 °C)
- Density
- 1.54 g/cm³