| Symbol | Ga |
| Atomic number | 31 |
| Group | 13 (Boron group) |
| Period | 4 |
| Block | p |
| Classification | Post-Transition Metal |
| Appearance | Silver-white |
| Color | Silver |
| Number of protons | 31 p+ |
| Number of neutrons | 39 n0 |
| Number of electrons | 31 e- |
| Phase at STP | Solid |
| Density | 5.91 g/cm3 |
| Atomic weight | 69.7231 u |
| Melting point | 302.915 K 29.765 °C 85.577 °F |
| Boiling point | 2673 K 2399.85 °C 4351.73 °F |
| Heat of vaporization | 256.06 kJ/mol |
| Electronegativity (Pauling Scale) | 1.81 |
| Electron affinity | 41 kJ/mol |
| Oxidation states | −5, −4, −3, −2, −1, +1, +2, +3 (an amphoteric oxide) |
| Ionization energies |
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| Prediction | Dmitri Mendeleev (1871) |
| Discovery and first isolation | Paul-Émile Lecoq de Boisbaudran (1875) |
Discovery of gallium In 1871, the existence of gallium was first predicted by Russian chemist Dmitri Mendeleev, who named it "eka-aluminium" from its position in his periodic table. He also predicted several properties of eka-aluminium that correspond closely to the real properties of gallium, such as its density, melting point, oxide character, and bonding in chloride. Gallium was discovered using spectroscopy by French chemist Paul Emile Lecoq de Boisbaudran in 1875 from its characteristic spectrum (two violet lines) in a sample of sphalerite. Later that year, Lecoq obtained the free metal by electrolysis of the hydroxide in potassium hydroxide solution. He named the element "gallia", from Latin Gallia meaning Gaul, after his native land of France. | |