Alkali Metal

6 elements

Highly reactive metals in Group 1 of the periodic table. They have one valence electron and readily form +1 cations. These soft, silvery metals react vigorously with water and are never found as free elements in nature.

3 Solid Li Lithium 6.941 u

MP: 180.5 °C BP: 1329.8 °C

11 Solid Na Sodium 22.99 u

MP: 97.8 °C BP: 882.9 °C

19 Solid K Potassium 39.098 u

MP: 63.6 °C BP: 758.9 °C

37 Solid Rb Rubidium 85.468 u

MP: — BP: —

55 Solid Cs Cesium 132.91 u

MP: — BP: —

87 Solid Fr Francium 223.0 u

MP: — BP: —

Comparison Table

#	Symbol	Name	Mass (u)	Melting Pt	Boiling Pt	Density	Phase
3	Li	Lithium	6.941	180.5 °C	1329.8 °C	0.534	Solid
11	Na	Sodium	22.99	97.8 °C	882.9 °C	0.971	Solid
19	K	Potassium	39.098	63.6 °C	758.9 °C	0.862	Solid
37	Rb	Rubidium	85.468	—	—	—	Solid
55	Cs	Cesium	132.91	—	—	—	Solid
87	Fr	Francium	223.0	—	—	—	Solid