Fm
257.000Fermium
Fermiyum
Fermium is a synthetic radioactive actinide with atomic number 100. It was discovered in Ivy Mike debris and is known for fermium-257, basic nuclear research, the fermium wall and the limits of heavy-element production.
100
257 g/mol
[Rn] 5f¹² 7s²
2 | 8 | 18 | 32 | 30 | 8 | 2
1.3
—
1526.8 °C
—
Albert Ghiorso
Fermium was discovered by Albert Ghiorso and collaborators in debris from the 1952 Ivy Mike hydrogen bomb test. It was named after Enrico Fermi, who led the first controlled nuclear chain reaction.
Fermium-255
Half-life: About 20.1 hours. Short-lived isotope produced in reactor and nuclear research contexts.Fermium-257
Half-life: About 100.5 days. Longest-lived fermium isotope and the main isotope for chemical research.- Fermium-257 in fundamental nuclear structure and actinide chemistry research
- Studies of spontaneous fission and heavy nuclei
- Research on the production limits of very heavy elements
- Trace chemistry of late actinides
Fermium has no biological role. It is synthetic, radioactive and produced only in very small quantities for nuclear research.
- Fermium is often described as the heaviest element reached by neutron-capture production routes in reactors.
- The “fermium wall” describes the difficulty of building heavier elements by neutron capture because heavier fermium isotopes fission quickly.
- Fermium is named after Enrico Fermi, whose work marks the start of the controlled nuclear reactor era.
- Fermium has atomic number 100 and symbol Fm.
- Its electron configuration is [Rn] 5f¹² 7s².
- Fermium commonly forms +3 compounds in trace chemistry.
- Remember Fm-257 for the longest-lived fermium isotope and the fermium wall concept.
What is the atomic number of fermium?
The atomic number of fermium is 100.
What is the electron configuration of fermium?
Fermium has the electron configuration [Rn] 5f¹² 7s².
What is fermium used for?
Fermium has no commercial use; it is used only in nuclear physics and actinide chemistry research.
What is fermium-257?
Fermium-257 is the longest-lived fermium isotope, with a half-life of about 100.5 days.
What is the fermium wall?
The fermium wall is the practical barrier to making heavier elements by neutron capture because heavier fermium isotopes undergo rapid spontaneous fission.