Gallium (Ga)
Gallium is element 31, a post-transition metal in period 4, group 13 of the periodic table. At room temperature it is a solid.
Electron configuration [Ar] 3d10 4s2 4p1
Electrons per shell 2, 8, 18, 3
Gallium data
| Atomic number | 31 |
|---|---|
| Symbol | Ga |
| Atomic mass | 69.723 u |
| Category | Post-transition metal |
| Group | 13 |
| Period | 4 |
| Block | p |
| State at 25 °C | solid |
| Melting point | 303 K (29.9 °C) |
| Boiling point | 2477 K (2203.9 °C) |
| Density | 5.904 g/cm³ |
| Electronegativity (Pauling) | 1.81 |
| Atomic radius | 126 pm |
| 1st ionization energy | 579 kJ/mol |
| Electron affinity | -29 kJ/mol |
| Oxidation states | +1, +2, +3 |
| Common ion charge | 3+ |
| Discovered | 1875 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through gallium’s configuration and its ions →
Where gallium sits
Gallium belongs to the post-transition metals. Its Pauling electronegativity of 1.81 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Gallium FAQ
What is the electron configuration of gallium?
Gallium (Z = 31) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1. In noble-gas shorthand that is [Ar] 3d10 4s2 4p1.
How many valence electrons does gallium have?
3 (outer shell (n = 4)).
What is the atomic mass of gallium?
The standard atomic weight of gallium is 69.723 u, so one mole weighs 69.723 g.
Is gallium a metal?
Yes. Gallium is a post-transition metal.
What is the charge of a gallium ion?
Gallium most commonly forms Ga3+.