81Tl204.38
Thallium
Post-transition metal · element 81 · group 13, period 6
Quick facts
| Symbol | Tl |
|---|---|
| Atomic number | 81 |
| Relative atomic mass | 204.38 |
| Category | Post-transition metal |
| Position | group 13, period 6 |
| State at 20 °C | Solid |
| Melting point | 304 °C |
| Boiling point | 1,473 °C |
| Density | 11.85 g/cm³ |
| Electronegativity | 1.62 |
| Electron configuration | [Xe] 4f14 5d10 6s2 6p1 |
About Thallium
Thallium has the symbol Tl and atomic number 81, which means every thallium atom has 81 protons in its nucleus and, in a neutral atom, 81 electrons. At room temperature it is a solid.
Post-transition metals are softer metals found to the right of the transition metals, with lower melting points.
It melts at 304 °C and boils at 1,473 °C.
Explore it
See where thallium sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.