Gallium

Element 31 · Post-transition metal

Specimen

Atomic number: 31
Atomic mass: 69.723
State at room temperature: Solid
Melting point: 29.76 °C
Boiling point: 2,204 °C
Density: 5.91 g/cm³
Discovered: 1875

Physical data from PubChem.¹

Can I eat it?

In food and water: Not needed, little harm known. Gallium has no known function in the human body. Animals absorb little gallium arsenide from the gut. Gallium nitrate is a medicine, and kidney damage limits the dose given into a vein. There are few studies of gallium in food. ²

The atom

Shell	Electrons
1 (K)	2
2 (L)	8
3 (M)	18
4 (N) outermost	3
Total	31

Configuration [Ar] 3d¹⁰ 4s² 4p¹

3d ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓

4s ↑ ↓

4p ↑

A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 31 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 Ar 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
Chitambar C. R., International Journal of Environmental Research and Public Health 7(5):2337, 2010. Medical Applications and Toxicities of Gallium Compounds .
- gallium has no known physiologic function in the human body
- renal toxicity was dose-limiting when gallium nitrate was administered as a brief intravenous infusion
- With oral administration, the majority of gallium and arsenide appears in the feces thus indicating that this compound has limited bioavailability

Specimen

Can I eat it?

The atom

Related elements

New elements by e-mail

Sources