31 Ga 69.723
Gallium
Post-Transition Metal
Gallium (Ga) is a chemical element with atomic number 31, classified as a post-transition metal. At room temperature it is a solid. It was discovered in 1875 by Lecoq de Boisbaudran.
Properties
- 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
- Phase at STP
- Solid
- Density
- 5.907 g/cm³
- Melting point
- 302.91 K (29.8 °C)
- Boiling point
- 2477 K (2203.8 °C)
- Electronegativity
- 1.81
- Atomic radius
- 136 pm
- Ionization energy
- 5.999 eV
- Discovery
- 1875 · Lecoq de Boisbaudran
Common uses
LEDs, semiconductors, solar panels, thermometers
Did you know?
Melts in your hand at 29.8°C but is essential for modern electronics.
Experiment with the elements
Gallium doesn't form any compounds in our lab yet, but the periodic table sandbox lets you combine dozens of other real elements into real compounds — water, table salt, ammonia and many more — with their true chemical formulas.