Francium

Element 87 · Alkali metal

Specimen

Atomic number: 87
Atomic mass: 223.02
State at room temperature: Solid
Melting point: 26.85 °C
Boiling point: Unknown
Density: Unknown
Discovered: 1939

Physical data from PubChem.¹

Can I eat it?

In food and water: Never made in amounts you could eat. Francium decays too fast to collect. Nobody has made or isolated an amount large enough to weigh. ²

The atom

Shell	Electrons
1 (K)	2
2 (L)	8
3 (M)	18
4 (N)	32
5 (O)	18
6 (P)	8
7 (Q) outermost	1
Total	87

Configuration [Rn] 7s¹

7s ↑

A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 87 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. Francium .
- It is very difficult to measure the properties of francium because it decays so fast. No weighable quantity of the element has been prepared or isolated

Specimen

Can I eat it?

The atom

Related elements

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Sources