Fm
Fermium
Element 100 · Actinide
Fermium (Fm)
Fermium is a radioactive metal also discovered in the debris of the Ivy Mike hydrogen bomb test.
- Actinide
- Period 7
- f-block series
- f-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [257]
- u
- Electron configuration
- [Rn] 5f12 7s2
- Melting point
- 1,526.9 °C
- 1,800 K
- Boiling point
- —
- Density
- —
- Electronegativity
- 1.3
- Pauling
- Atomic radius
- —
- 1st ionisation energy
- 6.5 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about fermium
- 01
Fermium is the heaviest element that can be made by neutron bombardment.
- 02
It has never been produced in weighable amounts.
- 03
The team kept its discovery confidential until 1955.
Applications
What is fermium used for?
- Research
History
Discovery & name origin
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 100
- Atomic mass
- [257] u
- Group
- Actinides (3)
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f12 7s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f12
- Electrons per shell
- 2, 8, 18, 32, 30, 8, 2
- Electronegativity (Pauling)
- 1.3
- Electron affinity
- —
- Atomic radius (van der Waals)
- —
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+3).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 1,800 K · 1,526.9 °C · 2,780.3 °F
- Boiling point
- —
- Density
- —
- Molar heat capacity
- —
- Appearance
- —
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Fermium questions
What is Fm on the periodic table?
Fm is the symbol for fermium, element 100 on the periodic table. It sits in period 7, in the f-block, in the actinide category, and has an atomic mass of [257].
What is the atomic number of fermium?
Fermium has atomic number 100, so every fermium atom has 100 protons in its nucleus. Its symbol is Fm and its atomic mass is [257].
Who discovered fermium?
Fermium was discovered by Albert Ghiorso in 1952 (United States). The name comes from from Enrico Fermi.
What is fermium used for?
Fermium is used for: research.
Is fermium a metal?
Yes. Fermium is a actinide, one of the metallic elements.
What is the electron configuration of fermium?
The electron configuration of fermium is [Rn] 5f12 7s2. Its 100 electrons are arranged in shells as 2, 8, 18, 32, 30, 8, 2.