Gallium (Ga)
Post-transition metal · p-block · period 4 · group 13
Silvery metal that melts in your hand.
Gallium (symbol Ga) is chemical element number 31, a post-transition metal in group 13, period 4 of the periodic table. Its standard atomic weight is 69.723 and its electron configuration is [Ar] 3d10 4s2 4p1. At room temperature it is a solid. Melts at 30 °C — a solid spoon of it turns liquid in a hot drink.
Properties
| Atomic number | 31 |
|---|---|
| Atomic mass | 69.723 |
| Category | Post-transition metal |
| Block | p-block |
| Group · Period | 13 · 4 |
| Electron configuration | [Ar] 3d10 4s2 4p1 |
| Electrons per shell | 2, 8, 18, 3 |
| State at 25 °C | solid |
| Melting point | 302.91 K |
| Boiling point | 2673 K |
| Density | 5.91 g/cm³ |
| Electronegativity (Pauling) | 1.81 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1875 · Paul-Émile Lecoq de Boisbaudran |
Key facts about Gallium
- Melts at 30 °C — a solid spoon of it turns liquid in a hot drink.
- Mendeleev predicted it as 'eka-aluminium' before it was found.
- Gallium nitride LEDs produce the bright blue and white light in modern screens and bulbs.
- Expands when it freezes, like water.
What Gallium is used for
LEDs and laser diodes, high-speed and solar-cell semiconductors, low-melting alloys, thermometers.
Where it sits in the periodic table
Gallium is in group 13, period 4, of the p-block. Its electron configuration [Ar] 3d10 4s2 4p1 means its outermost shell holds 3 electrons, which is what places it here and explains much of its chemistry. See Gallium on the interactive table →
Gallium — frequently asked questions
What is Gallium used for?
LEDs and laser diodes, high-speed and solar-cell semiconductors, low-melting alloys, thermometers.
Is Gallium radioactive?
No. Gallium has at least one stable isotope and is not radioactive.
What is the electron configuration of Gallium?
Gallium has the electron configuration [Ar] 3d10 4s2 4p1, which is 2, 8, 18, 3 electrons per shell.
What group and period is Gallium in?
Gallium is in group 13, period 4, in the p-block. Its outer shell holds 3 electrons.
Who discovered Gallium?
Gallium was discovered in 1875 by Paul-Émile Lecoq de Boisbaudran.