Promethium (Pm)
Promethium (Pm, element 61) is a lanthanide in period 6. Atomic mass 145, electron configuration [Xe] 4f⁵ 6s², uses and facts.
About Promethium
Promethium is a lanthanide with the symbol Pm and atomic number 61. It is a solid at room temperature, and it sits in period 6 of the periodic table. Promethium was discovered in 1945 by Jacob A. Marinsky.
Promethium key facts
- Atomic number: 61
- Symbol: Pm
- Atomic mass: 145 u
- Category: lanthanide
- Group: none (f-block)
- Period: 6
- State at room temperature: solid
- Electron configuration: [Xe] 4f⁵ 6s²
- Electronegativity (Pauling): 1.13
- Melting point: 1315 K (1041.85 °C)
- Boiling point: 3273 K (2999.85 °C)
- Density: 7.26 g/cm³
- Common oxidation states: +2, +3
Electron configuration
The electron configuration of promethium is [Xe] 4f⁵ 6s². The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells.
Uses of promethium
- Nuclear batteries
- Luminous paint (historical)
- Research
Did you know?
Promethium is the only lanthanide with no stable isotopes. It is named after Prometheus, the titan of Greek mythology.
Neighbouring elements
- Neodymium (Nd)
- Samarium (Sm)
- Lanthanum (La)
- Cerium (Ce)
- Praseodymium (Pr)
- Neodymium (Nd)
- Samarium (Sm)
- Europium (Eu)
- Gadolinium (Gd)
- Terbium (Tb)
Frequently asked questions
What is the atomic number of promethium?
The atomic number of promethium is 61, which means every promethium atom has 61 protons.
What is the electron configuration of promethium?
The electron configuration of promethium is [Xe] 4f⁵ 6s².
What group and period is promethium in?
Promethium is a lanthanide in period 6.
What state is promethium at room temperature?
Promethium is a solid at room temperature.
What is promethium used for?
Promethium is used for nuclear batteries, luminous paint (historical), research.