Fermium
Fermium is a synthetic element with symbol Fm and atomic number 100. It is a member of the actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
86 is the [Rn] core total across six shells.
At a glance
- Atomic number
- 100
- Atomic mass
- 257 u
- Phase
- Solid
- Density
- Unavailable
- Melting point
- 1,800 K
- Boiling point
- Unavailable
- First ionization energy
- 627 kJ/mol
- Electronegativity
- 1.3
- Electron affinity
- 33.96 kJ/mol
- Molar heat capacity
- Unavailable
- Period
- 7
- Appearance
- Unavailable
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.