Gallium (Ga): electron configuration, atomic mass and facts
Gallium (Ga) is element 31 of the periodic table, a post-transition metal in period 4, group 13. Its electron configuration is [Ar] 3d10 4s2 4p1, with electrons arranged in shells 2, 8, 18, 3, and its standard atomic weight is 69.723 u.
💡 Melts at 29.8 °C, so it melts in your hand.
▶ Watch Gallium’s electrons orbit in the interactive periodic tableGallium at a glance
| Symbol | Ga |
|---|---|
| Atomic number | 31 |
| Atomic mass | 69.723 u |
| Category | Post-transition metal |
| Group | 13 |
| Period | 4 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1 |
| Noble-gas shorthand | [Ar] 3d10 4s2 4p1 |
| Electrons per shell | 2, 8, 18, 3 |
| Outer-shell electrons | 3 |
| Electronegativity (Pauling) | 1.81 |
| State at 20 °C | solid |
Where is Gallium on the periodic table?
Gallium is in period 4, group 13, in the p-block. The period number matches its 4 electron shells, and the block names the subshell its last electrons fill. In the same group, Aluminium sits directly above it and Indium sits directly below it. Elements in one group have the same number of outer-shell electrons (3 here), which is why they react in similar ways.
How to work out the electron configuration of Gallium
Put 31 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p⁶ (10), 3s² (12), 3p⁶ (18), 4s² (20), 3d¹⁰ (30), 4p¹ (31). In shorthand, [Ar] stands for the 18 electrons of argon, giving [Ar] 3d¹⁰ 4s² 4p¹.
How electronegative is Gallium?
Gallium has a Pauling electronegativity of 1.81, ranking 43 of the 100 elements with a known value (fluorine is highest at 3.98). That is in the middle of the range.
Frequently asked questions
What is the electron configuration of Gallium?
The electron configuration of Gallium (Ga) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1. In noble-gas shorthand it is written [Ar] 3d10 4s2 4p1.
How many electrons does Gallium have in each shell?
Gallium has 31 electrons arranged in shells as 2, 8, 18, 3. It has 3 electrons in its outer shell.
What is the atomic mass of Gallium?
The standard atomic weight of Gallium is 69.723 u, so one mole of Gallium atoms has a mass of about 69.723 g.
Is Gallium a metal?
Yes. Gallium is a post-transition metal.
Explore nearby elements
More post-transition metals: Aluminium, Indium, Tin, Thallium, Lead, Bismuth. See all elements on the periodic table.