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Tantalum (Ta)

Tantalum is a chemical element of the periodic table with chemical symbol Ta and atomic number 73 with an atomic weight of 180.948 u and is classed as transition metal and is part of group 5 (vanadium group). Tantalum is solid at room temperature.

Tantalum in the periodic table

Atomic number73
Group5 (Vanadium group)
ClassificationTransition Metal
AppearanceGray blue
Color Gray
Number of protons73 p+
Number of neutrons108 n0
Number of electrons73 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.

Physical properties

Phase at STPSolid
Density16.69 g/cm3
Atomic weight180.948 u

Thermal properties

Melting point3290 K
3016.85 °C
5462.33 °F
Boiling point5731 K
5457.85 °C
9856.13 °F
Heat of vaporization737 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.5
Electron affinity31 kJ/mol
Oxidation states−3, −1, 0, +1, +2, +3, +4, +5
(a mildly acidic oxide)
Ionization energies
  1. 761 kJ/mol
  2. 1500 kJ/mol

Electron configuration for tantalum

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
Electrons per shell2, 8, 18, 32, 11, 2
Valence electrons 2
Valency electrons 5
Bohr model
TantalumElectron shell for Tantalum, created by Injosoft ABTa
Figure: Shell diagram of Tantalum (Ta) atom.
Orbital Diagram

The history of Tantalum

DiscoveryAnders Gustaf Ekeberg (1802)
Recognized as a distinct element byHeinrich 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.


List of unique identifiers for Tantalum in various chemical registry databases
CAS Number7440-25-7
ChemSpider ID22395
EC number231-135-5
PubChem CID Number23956