Symbol: Fm
Atomic number: 100
Category: actinides
Group: n/a
Period: 7
Block: f
Atomic weight: (257) g/mol
Electrons per shell: 2, 8, 18, 32, 30, 8, 2
CAS number: 7440-72-4
Phase: solid
Density: unknown
Melting point: 1800 K (1527 C, 2781 F)
Boiling point: unknown
Crystal structure: unknown
Oxidation states: 2, 3
Electronegativity: 1.3 (Pauling scale)
Name's origin: Enrico Fermi
Name's meaning: in honor of the nuclear physicist
- is a highly radioactive metallic transuranic element
- is made by bombarding plutonium with neutrons
- only small amounts of fermium have ever been produced or isolated - thus relatively little is known about its chemical properties
- there are no known uses of fermium outside of basic research
- does not occur naturally in any measurable quantities
- 17 radioisotopes of fermium have been characterized, with the most stable being fermium-257 with a half-life of 100.5 days
- fermium-255 was found in the debris of the first hydrogen bomb explosion