Periodic Table

Fermium

Actinide

Quick Facts about Fermium

Es
  • solid- state of matter at room temperature
  • Radioactive- no stable isotopes exist
  • +3- common oxidation states in compounds
Md

Fermium (Fm) is element 100 on the periodic table. Atomic mass of Fm: 257.0000 u. Fm is in period 7. Melting point of Fm: 1800.00 K.Density of Fm: 9.70 g/cm³.

Why Fermium Matters

Fermium in everyday life and industry

In Your Home

  • No commercial applications exist
  • Used only in scientific research
  • Only picogram quantities have been made

Industry Uses

NuclearHelps study nuclear stability

In Your Body

✗ Not essential

No biological role. Too rare and short-lived for biological studies.

Safety: Fermium is radioactive. Would be hazardous if enough existed.

Discovery of Fermium

Discovered by Argonne, Los Alamos, U of Calif in United States, 1953

Name origin: Named in honor of the scientist Enrico Fermi.

History & Events

1952
Named after Enrico Fermi
1952
Discovered in hydrogen bomb debris with einsteinium (1952)
1955
Discovery classified until 1955
1952
First element that cannot be made in macroscopic quantities by neutron capture

About Fermium

Radioactive metallic transuranic element, belongs to the actinoids. Ten known isotopes, most stable is Fm-257 with a half-life of 10 days. First identified by Albert Ghiorso and associates in the debris of the first hydrogen-bomb explosion in 1952.

Atomic Properties of Fm

Atomic Number of Fm
100
Atomic Mass of Fm
257.0000 u
Electron Configuration
[Rn] 5f12 7s2
Electronegativity
1.30
Block
f-block
Group
Period
7

Physical Properties of Fm

Phase (STP)
solid
Melting Point of Fm
1800.00 K
Boiling Point of Fm
Density of Fm
9.7000 g/cm3

Atomic Radii

Covalent
167 pm
Van der Waals
245 pm

Common Misconceptions

Wrong:Enrico Fermi discovered fermium.
Correct:Fermium honors Fermi for creating the first nuclear reactor (1942); the element was discovered by Ghiorso's team in H-bomb debris.
Wrong:Fermium can be produced in bulk like lighter actinides.
Correct:Fermium marks a boundary—heavier elements cannot be made in macroscopic quantities via neutron capture in reactors.
Wrong:Large amounts of fermium have been produced.
Correct:Only about 10 million fermium atoms have ever been produced in total—far less than a visible speck.

Isotopes of Fermium

Fermium has 0 naturally occurring isotopes, plus 1 notable radioactive isotope.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
257100Fm (Fm-257)Fermium-257 isotope257.0951061

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Uses

It has no significant commercial applications.

Sources

Produced by bombarding lighter transuranium elements with still lighter particles or by neutron capture.

Geochemistry

Goldschmidt
synthetic

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