Actinide

Fermium

Fermium (Fm) has atomic number 100. PubChem classifies it as actinide.

Atomic number

100

Symbol

Fm

Atomic weight (source value)

257.09511

Electron configuration

[Rn] 5f12 7s2

Standard state

Solid

Electronegativity (Pauling)

1.3

Melting point (K)

1800

Boiling point (K)

Not provided

Density (g/cm³)

Not provided

Oxidation states

+3

Understanding this entry

Atomic number is the number of protons in the nucleus. Properties are reference values and may depend on conditions and measurement conventions. An atomic weight is not the mass of every isotope. For elements without a standard atomic weight, a source may report an isotope mass number. Blank source values are shown as unavailable rather than estimated.

Further reading and reference: NIH PubChem source dataset ↗. Values and educational summaries are not a substitute for specialised advice.