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Thulium (Tm)

From Wikipedia, the free encyclopediaThulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.

Thulium in the periodic table

Atomic number69
Element categoryLanthanide

Physical properties

Phase at STPSolid
Density9.32 g/cm3
Atomic weight168.934 u
Melting point1818 K
1544.85 °C
2812.73 °F
Boiling point2223 K
1949.85 °C
3541.73 °F

Atomic properties

Electronegativity (Pauling Scale)1.25
Electron affinity99 kJ/mol
Oxidation states0, +2, +3
(a basic oxide)
Ionization energies
1596.7 kJ/mol
2 1160 kJ/mol
3 2285 kJ/mol
4 4120 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)[Xe] 4f13 6s2
Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f13 5s2 5p6 6s2
Electrons per shell2, 8, 18, 31, 8, 2


Discovered byPer Teodor Cleve
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