20 Ca 40.078
Calcium
alkaline earth metal
Properties
- Atomic number
- 20
- Atomic mass
- 40.078 u
- Category
- alkaline earth metal
- Group
- 2
- Period
- 4
- Block
- s-block
- State (room temp)
- Solid
- Outer-shell electrons
- 2
- Electronegativity
- 1 (Pauling)
- Density
- 1.55 g/cm³
- Melting point
- 841.85 °C
- Boiling point
- 1483.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
Noble-gas shorthand: [Ar] 4s²
Electrons per shell: 2, 8, 8, 2 — that's 2 in the outermost shell.
About Calcium
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.
- Discovered by Humphry Davy
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.