Gallium

Post-transition metal · atomic number 31

3169.7231GaGalliumSolidPost-transition metal

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).

Properties of Gallium

Element category	Post-transition metal
Atomic number	31
Atomic mass	69.7231 u
Phase at STP	Solid
Group	13
Period	4
Block	p
Electron configuration	[Ar] 3d10 4s2 4p1
Electrons per shell	2, 8, 18, 3
Electronegativity (Pauling)	1.81
Melting point	302.9146 K (30 °C)
Boiling point	2673 K (2400 °C)
Density	5.91 g/cm3
Discovered by	Lecoq de Boisbaudran

← Zinc · Periodic table · Germanium → Ge

About the post-transition metal group

Softer, lower-melting metals beside the transition block — aluminium, tin, lead — abundant in cans, foils, solders and pigments.

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