Symbol	Ta
Atomic number	73
Group	5 (Vanadium group)
Period	6
Block	d
Classification	Transition Metal

Appearance	Gray blue
Color	Gray

Number of protons	73 p+
Number of neutrons	108 n0
Number of electrons	73 e-

From Wikipedia, the free encyclopediaTantalum is a chemical element with symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, an antihero from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant.

Phase at STP	Solid
Density	16.69 g/cm3
Atomic weight	180.948 u

Melting point	3290 K 3016.85 °C 5462.33 °F
Boiling point	5731 K 5457.85 °C 9856.13 °F
Heat of vaporization	737 kJ/mol

Electronegativity (Pauling Scale)	1.5
Electron affinity	31 kJ/mol
Oxidation states	−3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Ionization energies	761 kJ/mol 1500 kJ/mol

Electron configuration Shorthand configuration	[Xe] 4f14 5d3 6s2
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d3 6s2
Electron configuration chart	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d3 6s2
Electrons per shell	2, 8, 18, 32, 11, 2
Valence electrons	2
Valency electrons	5
Bohr model	Figure: Shell diagram of Tantalum (Ta) atom.
Orbital Diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s

Discovery	Anders Gustaf Ekeberg (1802)
Recognized as a distinct element by	Heinrich Rose (1844)
Discovery of tantalum Tantalum was discovered in Sweden in 1802 by Anders Ekeberg, in two mineral samples – one from Sweden and the other from Finland. One year earlier, Charles Hatchett had discovered columbium (now niobium), and in 1809 the English chemist William Hyde Wollaston compared its oxide, columbite with a density of 5.918 g/cm3, to that of tantalum, tantalite with a density of 7.935 g/cm3. He concluded that the two oxides, despite their difference in measured density, were identical and kept the name tantalum. After Friedrich Wöhler confirmed these results, it was thought that columbium and tantalum were the same element. This conclusion was disputed in 1846 by the German chemist Heinrich Rose, who argued that there were two additional elements in the tantalite sample, and he named them after the children of Tantalus: niobium (from Niobe, the goddess of tears), and pelopium (from Pelops). The supposed element "pelopium" was later identified as a mixture of tantalum and niobium, and it was found that the niobium was identical to the columbium already discovered in 1801 by Hatchett.

CAS Number	7440-25-7
ChemSpider ID	22395
EC number	231-135-5
PubChem CID Number	23956