61
145 u
Pm
Promethium
Lanthanide
Atomic Structure
Physical State
Group
N/A
Period
6
Block
f
Electron Configuration
[Xe] 4f⁵ 6s²
Physical Properties
Atomic Mass:
145 u
Electronegativity:
1.13
Atomic Radius:
260 pm
Ionization Energy:
5.582 eV
Density:
7.26 g/cm³
Melting Point:
1315 K
Boiling Point:
3273 K
Historical Information
Discovered By:
Jacob A. Marinsky
Year Discovered:
1945