61
Pm
Promethium
Promethium
Promethium (Pm)
Lanthanides · Solid · Period 6 · Group 3
Element Properties
- Atomic Number
- 61
- Symbol
- Pm
- Atomic Mass
- 144.9128
- Category
- Lanthanides
- Standard State
- Solid
- Period
- 6
- Group
- 3
- Electronegativity
- —
- Atomic Radius
- 236
- Ionization Energy
- 5.55
- Electron Affinity
- —
- Oxidation States
- +3
- Melting Point
- 1315 K (1041.85 °C)
- Boiling Point
- 3273 K (2999.85 °C)
- Density
- 7.26
- Electron Configuration
- [Xe]6s2 4f5
- Year Discovered
- 1945
Electron shells
[Xe]6s2 4f5
Electrons are arranged in shells (principal energy levels) around the nucleus. The diagram is a schematic — orbitals in the same shell are not drawn separately.
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Frequently asked questions
What is the atomic number of Promethium?
The atomic number of Promethium is 61, which equals the number of protons in its nucleus.
What is the atomic mass of Promethium?
The atomic mass of Promethium is approximately 144.9128 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Promethium?
The electron configuration of Promethium is [Xe]6s2 4f5.
Where is Promethium in the periodic table?
Promethium is located in period 6, group 3.
When was Promethium discovered?
Promethium was discovered in 1945.
Related elements
Same group
21
Sc
Scandium
44.956
39
Y
Yttrium
88.906
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.24