81 Tl
Post-transition metal
Thallium
Highly toxic.
Properties of Thallium
- Atomic number (Z)
- 81
- Symbol
- Tl
- Atomic mass
- 204.38 g/mol
- Category
- Post-transition metal
- Group
- 13
- Period
- 6
- Electron configuration
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹
- Electronegativity (Pauling)
- 1.62
- Atomic radius
- 156 pm
- First ionization energy
- 589 kJ/mol
- Melting point
- 577 K (303.9 °C)
- Boiling point
- 1746 K (1472.8 °C)
- Density
- 11.85 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1861