The periodic table/Cesium

Cesium (US), or caesium, is a chemical element.

Discovery
Two German scientists (Gustav Kirchhoff and Robert Bunsen), in 1860, discovered Cesium in samples of mineral water in Bad Dürkheim, a spa town in Germany. Because of two blue lines from its emission spectrum, they chose the name, caesius, which is Latin for "sky blue".

Quick Facts
Name: Cesium

Symbol: Cs

Date of Discovery: 1860

Discoverer: Fustov Kirchoff

Atomic number: 55

Atomic Mass: 132.90546 amu

Classification: Alkaline Metal

Protons: 55

Electrons: 55

Neutrons: 78

Color: Silver

Crystal Structure: Cubic

Melting Point: 28.5 °C

Boiling Point: 678.4 °C