Gallium (Ga) – element 31
Gallium is a chemical element with the symbol Ga and atomic number 31. It is a post-transition metal in group 13, period 4 of the periodic table (p-block), and is a solid at room temperature.
Gallium (Ga) has atomic number 31, atomic mass 69.723 u and electron configuration [Ar] 3d10 4s2 4p1.
Gallium facts
| Symbol | Ga |
|---|---|
| Atomic number | 31 |
| Atomic mass | 69.723 u (g/mol) |
| Category | post-transition metal |
| Group | group 13 |
| Period | 4 |
| Block | p-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 |
| Noble-gas notation | [Ar] 3d10 4s2 4p1 |
| Electrons per shell | 2, 8, 18, 3 |
| Valence electrons | 3 |
Bohr model and shells
Gallium has 31 electrons in 4 shells: 2, 8, 18, 3. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 302.915 K (29.8 °C) |
|---|---|
| Boiling point | 2673 K (2399.8 °C) |
| Density | 5.91 g/cm³ |
| Electronegativity (Pauling) | 1.81 |
| Electron affinity | 41 kJ/mol |
| Ionization energies | 578.8, 1979.3, 2963 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 25.86 J/(mol·K) |
| Discovered by | Lecoq de Boisbaudran |
Use the atomic mass in the molar mass calculator for any formula containing Ga.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of gallium?
The atomic mass of gallium is 69.723 u, so one mole of gallium atoms weighs 69.723 g.
What is the electron configuration of gallium?
Gallium has 31 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹, or [Ar] 3d¹⁰ 4s² 4p¹ in noble-gas notation. Electrons per shell: 2, 8, 18, 3.
How many valence electrons does gallium have?
Gallium has 3 valence electrons (group 13).
Is gallium a metal?
Yes. Gallium is a post-transition metal.
Where is gallium on the periodic table?
Gallium is in group 13, period 4, in the p-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.