Cesium

55 Atomic Number

Atomic Weight 132.91

Melting Point 28.44°C

Boiling Point 671°C

Element & Symbol	Atomic Number	Major Use(s)
Cesium (Cs)	55	Atomic clocks (definition of the second), drilling fluids, photoelectric cells.

Cesium is a silvery-gold, soft alkali metal; it is the most reactive metal and liquid near room temperature.