Gallium

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-

From Wikipedia, the free encyclopediaGallium 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).

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	578.8 kJ/mol 1979.3 kJ/mol 2963 kJ/mol 6180 kJ/mol

Electron configuration Shorthand configuration	[Ar] 3d10 4s2 4p1
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1
Electron configuration chart	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1
Electrons per shell	2, 8, 18, 3
Valence electrons	3
Valency electrons	3,1
Bohr model	Figure: Shell diagram of Gallium (Ga) atom.
Orbital Diagram	1s 2s 2p 3s 3p 3d 4s 4p

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.

Original word	Gallia
Language of origin	Latin
Name source	Place
Meaning	“France / Gaul”
Country	France
Naming The name is derived from the Latin name Gallia, the old name of France, in honor of its discoverer's home country.

CAS Number	7440-55-3
ChemSpider ID	4514603
EC number	231-163-8
PubChem CID Number	5360835