Thulium (Tm)
Thulium (Tm, element 69) is a lanthanide in period 6. Atomic mass 168.934, electron configuration [Xe] 4f¹³ 6s², uses and facts.
About Thulium
Thulium is a lanthanide with the symbol Tm and atomic number 69. It is a solid at room temperature, and it sits in period 6 of the periodic table. Thulium was discovered in 1879 by Per Teodor Cleve.
Thulium key facts
- Atomic number: 69
- Symbol: Tm
- Atomic mass: 168.934 u
- Category: lanthanide
- Group: none (f-block)
- Period: 6
- State at room temperature: solid
- Electron configuration: [Xe] 4f¹³ 6s²
- Electronegativity (Pauling): 1.25
- Melting point: 1818 K (1544.85 °C)
- Boiling point: 2223 K (1949.85 °C)
- Density: 9.32 g/cm³
- Common oxidation states: +2, +3
Electron configuration
The electron configuration of thulium is [Xe] 4f¹³ 6s². The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells.
Uses of thulium
- Portable X-ray devices
- Lasers
- Research
Did you know?
Thulium is the rarest of the naturally occurring lanthanides. Its name comes from 'Thule', an ancient name for Scandinavia.
Neighbouring elements
- Erbium (Er)
- Ytterbium (Yb)
- Lanthanum (La)
- Cerium (Ce)
- Praseodymium (Pr)
- Neodymium (Nd)
- Promethium (Pm)
- Samarium (Sm)
- Europium (Eu)
- Gadolinium (Gd)
Frequently asked questions
What is the atomic number of thulium?
The atomic number of thulium is 69, which means every thulium atom has 69 protons.
What is the electron configuration of thulium?
The electron configuration of thulium is [Xe] 4f¹³ 6s².
What group and period is thulium in?
Thulium is a lanthanide in period 6.
What state is thulium at room temperature?
Thulium is a solid at room temperature.
What is thulium used for?
Thulium is used for portable X-ray devices, lasers, research.