Potassium Scandium

Calcium (Ca)

From Wikipedia, the free encyclopediaCalcium 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.

Calcium in the periodic table

Symbol

Atomic number

Group

Period

Block

Element category

Alkaline Earth Metal

Physical properties

Phase at STP

Solid

Density

1.55 g/cm³

Atomic weight

40.0784 u

Melting point

1115 K
841.85 °C
1547.33 °F

Boiling point

1757 K
1483.85 °C
2702.93 °F

Atomic properties

Electronegativity (Pauling Scale)

Electron affinity

2.37 kJ/mol

Oxidation states

+1, +2
(a strongly basic oxide)

Ionization energies

1	589.8 kJ/mol
2	1145.4 kJ/mol
3	4912.4 kJ/mol
4	6491 kJ/mol
5	8153 kJ/mol
6	10496 kJ/mol
7	12270 kJ/mol
8	14206 kJ/mol
9	18191 kJ/mol
10	20385 kJ/mol
11	57110 kJ/mol
12	63410 kJ/mol
13	70110 kJ/mol
14	78890 kJ/mol
15	86310 kJ/mol
16	94000 kJ/mol
17	104900 kJ/mol
18	111711 kJ/mol
19	494850 kJ/mol
20	527762 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)

[Ar] 4s²

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

Electrons per shell

2, 8, 8, 2

History

Discovered

1808

Discovered by

Humphry Davy