Caesium was discovered by German chemists, Robert Wilhelm Bunsen and Gustav Robert Kirchhoff, in 1860 by the newly developed method of flame spectroscopy.
Name: Caesium
Symbol: Cs
Atomic number: 55
Atomic weight: 132.91
State: solid
Group, period, block: 1, 6, s
Color: silvery gold
Classification: alkali metal
Electron configuration: 6s1
2,8,18,18,8,1
Physical properties
Density: 1.93 g/cm-3
Melting point: 301.59 K, 28.44 °C, 83.19 °F
Boiling point: 944 K, 671 °C, 1240 °F
Atomic properties
Oxidation states: 1
Electronegativity: 0.79 (Pauling scale)
Ionization energies: 1st: 375.7 kJ·mol-1
Covalent radius: 244±11 pm
Van der Waals radius: 343 pm
- Cs
Electron Configuration
Isotopes
There is one naturally occurring isotope of caesium exists, 133Cs.