61Pm
Promethium
LanthanidePromethium (Pm) is element 61, a lanthanide, in period 6 of the periodic table. Its atomic mass is usually given as 145, it melts at 1042 °C and boils at 3000 °C. Discovered by Chien Shiung Wu, 1945.
Atomic Number61
SymbolPm
NamePromethium
Atomic Weight145 u
CategoryLanthanide
Period6
Melting Point1042 °C
Boiling Point3000 °C
Density7.26 g/cm³
Electron Config[Xe] 4f5 6s2
Discovered ByChien Shiung Wu, 1945