Fermium

Element 100 · Actinide

Specimen

Atomic number: 100
Atomic mass: 257.095
State at room temperature: Solid
Melting point: 1,527 °C
Boiling point: Unknown
Density: Unknown
Discovered: 1952

Physical data from PubChem.¹

Can I eat it?

In food and water: Never made in amounts you could eat. Reactors make fermium only in very small amounts. All its isotopes are short-lived. Fermium has no use outside research. ²

The atom

Shell	Electrons
1 (K)	2
2 (L)	8
3 (M)	18
4 (N)	32
5 (O)	30
6 (P)	8
7 (Q) outermost	2
Total	100

Configuration [Rn] 5f¹² 7s²

5f ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↑

7s ↑ ↓

A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 100 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Rn core, with one arrow per electron.

Related elements

Sources

1

National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

Atomic mass, electron configuration, melting and boiling points, density and discovery year for all 118 elements.
2
Los Alamos National Laboratory, Periodic Table of Elements, 2026. Fermium .
- Because of the short half-lives of all fermium isotopes, and the fact that only very small amounts of fermium can be produced, fermium has no applications beyond basic scientific research.

Specimen

Can I eat it?

The atom

Related elements

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Sources