Quick answerPromethium (Pm) is a lanthanide with atomic number 61 and a mass number of 145 (the most stable isotope), in period 6. It was discovered by Marinsky, Glendenin, and Coryell in 1945. It is used for nuclear batteries and luminous paint. Its electron configuration is [Xe] 4f5 6s2.
Promethium is a radioactive lanthanide with no stable form, once used in glowing paint and nuclear batteries for space.
Key facts
| Symbol | Pm |
|---|---|
| Atomic number | 61 |
| Atomic mass | [145] — mass number of the most stable isotope |
| Category | lanthanide |
| Group | — (f-block element, no group number) |
| Period | 6 |
| Block | f-block |
| Electron configuration | [Xe] 4f5 6s2 |
| Discovered | Marinsky, Glendenin, and Coryell, 1945 |
| Uses | nuclear batteries, luminous paint, thickness gauges, research |
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Keep exploring
- Periodic table — all 118 elements
- Lanthanum (La) — another lanthanide, atomic number 57
- Cerium (Ce) — another lanthanide, atomic number 58
- Praseodymium (Pr) — another lanthanide, atomic number 59
- Neodymium (Nd) — another lanthanide, atomic number 60
- Samarium (Sm) — another lanthanide, atomic number 62
- Europium (Eu) — another lanthanide, atomic number 63
- Gadolinium (Gd) — another lanthanide, atomic number 64
- Terbium (Tb) — another lanthanide, atomic number 65
- Dysprosium (Dy) — another lanthanide, atomic number 66
- Holmium (Ho) — another lanthanide, atomic number 67
- All lanthanide elements — on the periodic table
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.