Tm
Thulium
Atomic number: 69Mass: 168.934 uCategory: Lanthanide
About Thulium
Thulium is the least abundant of the rare earth elements that naturally occur. It is an easily workable metal with a bright silvery-gray lustre. Thulium is used in portable X-ray devices and surgical lasers.
Properties
Period
6
Group
N/A
Block
F
Category
Lanthanide
Electronegativity
1.25 (Pauling)
Ionization Energy
596.7 kJ/mol
Melting Point
1818 K (1545°C)
Boiling Point
2223 K (1950°C)
Density
9.32 g/cm³
Oxidation States
+3
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹³ 5s² 5p⁶ 6s²
[Xe] 4f¹³ 6s²
Shell 1:2e⁻
Shell 2:8e⁻
Shell 3:18e⁻
Shell 4:31e⁻
Shell 5:8e⁻
Shell 6:2e⁻
Real-World Uses
Portable X-ray units
Surgical lasers
Magnetic materials
Fluorescent lamps
Doping fibre optic cables
Fun Fact
Thulium is so rare that almost no one has ever seen it — yet it's used in portable X-ray machines that don't need electricity!