Thallium (Tl)
Thallium
Thallium (Tl) is a post-transition metal in period 6, group 13. Its relative atomic mass is 204.38 and the molar mass of the atom is 204.38 g/mol.
Atomic number 81
Atomic mass 204.38
Molar mass 204.38 g/mol
Category Post-transition metal Solid
Properties of thallium
| Atomic number | 81 |
|---|---|
| Symbol | Tl |
| Latin name | Thallium |
| Relative atomic mass | 204.38 |
| Molar mass | 204.38 g/mol |
| Group, period, block | 13, 6, p |
| Category | Post-transition metal |
| State at 20 °C | Solid |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹ |
| Electronegativity (Pauling) | 1.62 |
| Atomic radius | 190 pm |
Electron configuration of thallium
Electrons per shell
K2L8M18N32O18P3
Full notation
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p¹
Noble-gas notation
81 protons · 81 electrons[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹
Formula and compounds of thallium
Simple substanceTlthalliumMolar mass of Tl: 204.38 g/mol
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Frequently asked questions
The relative atomic mass of thallium is 204.38, so the molar mass of the atom is 204.38 g/mol.
Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p¹. Noble-gas notation: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹.