Caesium was discovered by Gustav Kirchhoff, Robert Bunsen at 1860 in Germany.
Origin of name: from the Latin word "caesius" meaning "sky blue" or "heavenly blue".
Atomic Number: 55
Atomic Weight: 132.9054519
Melting Point: 301.59 K (28.44°C or 83.19°F)
Boiling Point: 944 K (671°C or 1240°F )
Density: 1.93 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 6 Group Number: 1 Group Name: Alkali Metal