Gallium (Ga)
Element 31 · Post-transition metal · atomic mass 69.723 u · group 13, period 4
Electron shells: 2, 8, 18, 3
Gallium melts at 30 °C, so it will liquefy in your hand, yet does not boil until well over 2000 °C. Its compounds run the LEDs and radio chips in modern electronics.
A gallium teaspoon will melt into a puddle in a cup of hot tea.
- Atomic number
- 31
- Atomic mass
- 69.723 u
- Electron configuration
- [Ar] 4s² 3d¹⁰ 4p¹
- Group · period · block
- 13 · 4 · p
- Oxidation states
- +3
- Electronegativity
- 1.81 (Pauling)
- Melting point
- 29.76 °C
- Boiling point
- 2,204 °C
- Density
- 5.91 g/cm³
- State at 20 °C
- Solid
- Appearance
- Soft, silvery-blue metal
- Discovered
- Paul-Émile Lecoq de Boisbaudran, 1875
31 protons, and 31 electrons when neutral
IUPAC standard atomic weight
Boron group
What Gallium is used for
- LEDs and laser diodes
- Gallium nitride fast chargers and 5G amplifiers
- Solar cells
- Low-melting alloys
Atomic structure of Gallium
A neutral gallium atom has 31 protons and 31 electrons. Its most common isotope carries about 39 neutrons, which is where the mass number 70 comes from. Change the neutron count and you have a different isotope of gallium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 3. In orbital notation that is [Ar] 4s² 3d¹⁰ 4p¹, leaving 3 valence electrons in the outer shell — the ones that do the chemistry.
3D electron orbitals
See where Gallium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Gallium sits in the periodic table
Metals to the right of the d-block. Softer, lower-melting and more brittle than the transition metals, with more covalent character in their bonding.
Discovery and naming
Gallium was discovered by Paul-Émile Lecoq de Boisbaudran in 1875. Its name comes from Latin Gallia, "France".
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Gallium?
The standard atomic weight of Gallium is 69.723 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Gallium have?
Gallium has 31 protons, because the atomic number is the proton count and that is what makes an atom Gallium at all. A neutral Gallium atom has the same number of electrons, 31. The neutron count varies by isotope; the most common one has about 39, since 70 − 31 = 39.
What is the electron configuration of Gallium?
The electron configuration of Gallium is [Ar] 4s² 3d¹⁰ 4p¹. Its electrons are arranged 2, 8, 18, 3 across 4 shells.
Is Gallium a metal?
Yes. Gallium is classified as a post-transition metal, on the metallic side of the table.
What group and period is Gallium in?
Gallium is in group 13 (the boron group), period 4, in the p-block. The group is its column and the period is its row.
What is the charge of Gallium?
Gallium most commonly forms a 3+ ion. It has 3 outer electrons available to lose.
What is the melting point of Gallium?
Gallium melts at 29.76 °C and boils at 2,204 °C. That puts it in the solids at everyday temperatures.
What is Gallium used for?
LEDs and laser diodes, Gallium nitride fast chargers and 5G amplifiers, Solar cells, Low-melting alloys. Gallium melts at 30 °C, so it will liquefy in your hand, yet does not boil until well over 2000 °C.
Who discovered Gallium, and where does its name come from?
Gallium (Ga) was discovered by Paul-Émile Lecoq de Boisbaudran in 1875. The name comes from Latin Gallia, "France".