69
Tm
168.934
Thulium
Lanthanide
Period 6
Block f
Thulium is a chemical element of the periodic table with chemical symbol Tm and atomic number 69 with an atomic weight of 168.934 u and is classed as lanthanide. Thulium is solid at room temperature.
Thulium in the periodic table
| Symbol | Tm |
| Atomic number | 69 |
| Group | - |
| Period | 6 |
| Block | f |
| Classification | Lanthanide |
| Appearance | Silvery gray |
| Color | Silver |
| Number of protons | 69 p+ |
| Number of neutrons | 100 n0 |
| Number of electrons | 69 e- |
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.
Physical properties
| Phase at STP | Solid |
| Density | 9.32 g/cm3 |
| Atomic weight | 168.934 u |
Thermal properties
| Melting point | 1818 K 1544.85 °C 2812.73 °F |
| Boiling point | 2223 K 1949.85 °C 3541.73 °F |
| Heat of vaporization | 191 kJ/mol |
Atomic properties
| Electronegativity (Pauling Scale) | 1.25 |
| Electron affinity | 99 kJ/mol |
| Oxidation states | 0, +2, +3 (a basic oxide) |
| Ionization energies |
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Electron configuration for thulium
Electron configuration Shorthand configuration | [Xe] 4f13 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f13 5s2 5p6 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration chart |
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| Electrons per shell | 2, 8, 18, 31, 8, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Valency electrons | 3 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Bohr model | Figure: Shell diagram of Thulium (Tm) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||
Orbital Diagram
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The history of Thulium
| Discovery and first isolation | Per Teodor Cleve (1879) |
Discovery of thulium Thulium was discovered by Swedish chemist Per Teodor Cleve in 1879 by looking for impurities in the oxides of other rare earth elements (this was the same method Carl Gustaf Mosander earlier used to discover some other rare earth elements). Cleve started by removing all of the known contaminants of erbia (Er2O3). Upon additional processing, he obtained two new substances; one brown and one green. The brown substance was the oxide of the element holmium and was named holmia by Cleve, and the green substance was the oxide of an unknown element. Cleve named the oxide thulia and its element thulium after Thule, an Ancient Greek place name associated with Scandinavia or Iceland. Thulium's atomic symbol was initially Tu, but later changed to Tm. | |
| Original word | Thule |
| Language of origin | Greek |
| Name source | Place |
| Meaning | “Thule (northern lands)” |
Naming The name is derived from Thule, the classical Greek and Roman name for the northernmost edge of the known world, often identified with Scandinavia. | |