55Cs
Element 55
Cesium
Alkali metals
Caesium or cesium is a chemical element with symbol Cs and atomic number 55.
Key data
- Atomic number
- 55
- Atomic mass
- 132.905 u
- Group / Period
- 1 / 6
- Block
- s-block
- Phase at STP
- Solid
- Density
- 1.93 g/cm³
- Melting point
- 28.6 °C
- Boiling point
- 670.9 °C
- Electron configuration
- [Xe] 6s1
Common uses
- •Atomic clocks (defines second)
- •Drilling fluids
- •Photocells
Discovery
Year: 1860
Discovered by: Robert Bunsen
Frequently asked questions
What is the atomic number of Cesium?
Cesium has atomic number 55. Its symbol is Cs and its atomic mass is 132.905 u.
What category of element is Cesium?
Cesium is classified as alkali metals. It sits in group 1, period 6 of the periodic table.
What is Cesium used for?
Common uses of Cesium include: Atomic clocks (defines second), Drilling fluids, Photocells.
When was Cesium discovered?
Cesium was discovered in 1860 by Robert Bunsen.
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