Atomic Number:55

Protons: 55


Neutrons: 78

Average Atomic Mass: 132.905 amu

Isotopes: Cs-129, Cs-130, Cs-131, Cs-132 ,Cs-133, Cs-134, Cs-135, Cs-136, Cs-137

Discovery: Cesium was discovered by Gustav Kirchhoff, Robert Bunsen at 1860 in Germany.

Name: The name Cesium comes from the Latin word Caesius meaning sky blue.

Uses: used as a catalyst in the hydrogenation of a few organic compounds
  • the metal can be used in ion propulsion systems. Although not usable in the earth's atmosphere, 1 kg of Cesium in outer space could propel a vehicle 140 times as far as the burning of the same amount of any known liquid or solid.
  • used in atomic clocks
  • because of its high oxygen affinity, the metal is used as a "getter" in electron tubes
  • used in photoelectric cells and vacuum tubes
  • IR lamps

Interesting Facts: Cesium (spelled Caesium in the UK) is the most electropositive of all naturally occurring elements; in other words, is the very reactive.