3169.723GaGallium
Gallium (Ga) — element 31post-transition metal · group 13, period 4
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 (the p-block), with a standard atomic mass of 69.723 u. At room temperature (25 °C) gallium is a solid.
💡 Known for: Melts in your hand at 29.8 °C; gallium arsenide and gallium nitride power LEDs and high-frequency chips.
# Gallium properties
| Symbol | Ga |
|---|---|
| Atomic number | 31 |
| Atomic mass | 69.723 u |
| Category | post-transition metal |
| Group | 13 |
| Period | 4 |
| Block | p-block |
| Electron configuration | [Ar] 3d¹⁰ 4s² 4p¹ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹ |
| Electrons per shell | 2, 8, 18, 3 |
| Protons / electrons | 31 / 31 |
| State at 25 °C | solid |
| Melting point | 302.91 K (29.8 °C, 85.6 °F) |
| Boiling point | 2477 K (2203.8 °C, 3998.9 °F) |
| Density | 5.907 g/cm³ |
| Electronegativity (Pauling) | 1.81 |
| First ionization energy | 5.999 eV |
| Atomic radius | 136 pm |
| Discovered | 1875 |
# Electron configuration of gallium
The electron configuration of gallium is [Ar] 3d¹⁰ 4s² 4p¹, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹. Its 31 electrons fill 4 shells as 2, 8, 18, 3, so the outermost shell holds 3 electrons. As a group 13 element, gallium has 3 valence electrons.
# Related elements
ZnZincprevious elementGeGermaniumnext elementBBorongroup 13AlAluminiumgroup 13InIndiumgroup 13TlThalliumgroup 13NhNihoniumgroup 13SnTinpost-transition metalPbLeadpost-transition metalBiBismuthpost-transition metalPoPoloniumpost-transition metalFlFleroviumpost-transition metalMcMoscoviumpost-transition metalLvLivermoriumpost-transition metal
# Gallium FAQ
What is the atomic number of gallium?
The atomic number of gallium is 31: every gallium atom has 31 protons in its nucleus. Its symbol is Ga.
What is the atomic mass of gallium?
The standard atomic mass of gallium is 69.723 u.
What is the electron configuration of gallium?
Gallium's electron configuration is [Ar] 3d¹⁰ 4s² 4p¹ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹), with 2, 8, 18, 3 electrons per shell.
Is gallium a metal?
Yes. Gallium is a post-transition metal, one of the metals.
What is the melting point of gallium?
Gallium melts at 302.91 K (29.8 °C, 85.6 °F) and boils at 2477 K (2203.8 °C, 3998.9 °F).
What is gallium used for / known for?
Melts in your hand at 29.8 °C; gallium arsenide and gallium nitride power LEDs and high-frequency chips.