81 Tl 204.38
Thallium
post-transition metal
Properties
- Atomic number
- 81
- Atomic mass
- 204.38 u
- Category
- post-transition metal
- Group
- 13
- Period
- 6
- Block
- p-block
- State (room temp)
- Solid
- Outer-shell electrons
- 3
- Electronegativity
- 1.62 (Pauling)
- Density
- 11.85 g/cm³
- Melting point
- 303.85 °C
- Boiling point
- 1472.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p¹
Noble-gas shorthand: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹
Electrons per shell: 2, 8, 18, 32, 18, 3 — that's 3 in the outermost shell.
About Thallium
Thallium is a chemical element with symbol Tl and atomic number 81. This soft gray post-transition metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air.
- Discovered by William Crookes
- Appearance: silvery white
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.