20
Ca
calcium
40.078

General properties

Group
group 2 (alkaline metals)
Period
period 4
Category
alkaline earth metals
Standard atomic weight
40.078(4)
Melting point
1115 K (842 °C)
Boiling point
1757 K (1484 °C)
Phase at STP
solid

Additional properties

Block
s-block
Electron configuration
[Ar] 4s²
Electrons per shell
2, 8, 8, 2
Electronegativity
1.00
Density
1.55 g/cm³
Oxidation states
+1, +2 (a strongly basic oxide)
CAS Number
7440-70-2