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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

Atomic mass from IUPAC.1 Other physical data from PubChem.2

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. 3

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The atom

Ga
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) outermost 3
Total31

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

Group 13
B Boron Al Aluminium In Indium Tl Thallium Nh Nihonium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

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

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    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
  4. 4

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.