Discovered By: Robert Wilhelm Bunsen, Gustav Kirchhoff
Discovery year: 1860

The following table showing some properties of Caesium(Cs):

Table Example
Atomic number 55
Group 1
Period 6
Block s
Electrons 55
Protons 55
Neutrons 78
Atomic weight 132.90545196
Oxidation states +1
Ionic charge Cs^+


Table Example
Electrons per shell K2 L8 M18 N18 O8 P1
Electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^1
Atomic radius 298 pm
Covalent radius 244 pm
Boiling point 671°C
Melting point 28.44°C
Phase Solid
Fusion heat 2.09 kJ.mol^-1
Specific heat 242 J.kg^-1.K^-1
Vaporization heat 65 kJ.mol^-1


Table Example
Color Yellow
Brinell hardness 0.14 MPa
Bulk modulus 1.6 GPa
Density 1879 kg.m^-3
Liquid density 1843 kg.m^-3
Mohs hardness 0.2
Molar volume 7.073*10^-5 m^3.mol^-1
Young's modulus 1.7 GPa
Electrical conductivity 5*10^6 S.m^-1
Electrical type Conductor


Table Example
Magnetic type Paramagnetic
Volume magnetic susceptibilityt 5.26*10^-6
Resistivity 2*10^-7 Ohm.m
Electronegativity 0.79
Valence 1
Electron affinity 45.5 kJ.mol^-1
First ionization energy 375.7 kJ.mol^-1
Radioactive No
Neutron cross section 29 barn