31
Ga
Gallium
69.723
Gallium (Ga)
Post-Transition MetalGroup 13Period 4p-block-block
Gallium is a chemical element with symbol Ga and atomic number 31. Elemental gallium does not occur in free form in nature, but as the gallium(III) compounds that are in trace amounts in zinc ores and in bauxite. Gallium is a soft, silvery metal, and elemental gallium is a brittle solid at low temperatures, and melts at 29.76 °C (85.57 °F) (slightly above room temperature).
Latin name: Gallium
Atomic Number
31
Atomic Mass
69.723 g/mol
Phase (STP)
Solid
Electron Config.
[Ar] 3d¹⁰ 4s² 4p¹
General
SymbolGa
Atomic Number31
Atomic Mass69.723 g/mol
CategoryPost-Transition Metal
Group13
Period4
Blockp-block
Electron Configuration[Ar] 3d¹⁰ 4s² 4p¹
Valence Electrons13
Coloursilvery-blue metallic
Appearancesilver-white
CAS NumberCAS7440-55-3
Physical Properties
Phase (STP)Solid
Density5.907 g/cm³
Melting Point29.76°C · 85.57°F · 302.91 K
Boiling Point2203.85°C · 3998.93°F · 2477.00 K
Atomic Properties
Atomic Radius136 pm
Electronegativity1.81 Pauling
Ionization Energy579 kJ/mol
Oxidation States+3, +1
Ion ChargeGa3+/Ga+
Thermodynamic
Molar Heat25.86 J/(mol·K)
Crystal Structure
Crystal Structureorthorhombic
Mechanical Properties
Mohs Hardness1.5
Abundance
In Earth's Crust0.1800%
Discovery & History
Discovery Year1875
Discovered ByPaul Émile Lecoq de Boisbaudran
Country of DiscoveryFrance
Isotopes of Gallium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Ga-69 | 60.108% | Stable | — |
| Ga-71 | 39.892% | Stable | — |