Discovered By: Jacob A. Marinsky, Lawrence Glendenin, Charles D. Coryell
Discovery year: 1945

The following table showing some properties of Promethium(Pm):

Table Example
Atomic number 61
Group n/a
Period 6
Block f
Electrons 61
Protons 61
Neutrons 84
Atomic weight 145
Oxidation states +3
Ionic charge Pm^3+


Table Example
Electrons per shell K2 L8 M18 N23 O8 P2
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^2 4f^5
Atomic radius 205 pm
Covalent radius 199 pm
Boiling point 3000°C
Melting point 1100°C
Thermal conductivity 15 W.m^-1.K^-1
Phase Solid
Fusion heat 7.7 kJ.mol^-1
Thermal expansion 1.1*10^-5 K^-1


Table Example
Vaporization heat 290 kJ.mol^-1
Color Silver
Bulk modulus 33 GPa
Density 7264 kg.m^-3
Molar volume 2*10^-5 m^3.mol^-1
Poisson ratio 0.28
Shear modulus 18 GPa
Electrical conductivity 1.3*10^6 S.m^-1


Table Example
Lifetime 8.06*10^8 s
Young's modulus 46 GPa
Electrical type Conductor
Half life 5.59*10^8 s
Resistivity 7.5*10^-7 Ohm.m
Decay mode Electron capture (β-decay)
Valence 3
Electron affinity 50 kJ.mol^-1
First ionization energy 540 kJ.mol^-1
Radioactive Yes
Neutron cross section 8400 barn