Thallium vs Astatine
| Property | Tl Thallium | At Astatine |
|---|---|---|
| Atomic number | 81 | 85 |
| Symbol | Tl | At |
| Name | Thallium | Astatine |
| Category | post-transition-metal | halogen |
| Standard Atomic Weight | 204.3835 u | 210 u |
| Period | 6 | 6 |
| Group | 13 | 17 |
| Block | p | p |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f145d106p1 | [Xe]6s24f145d106p5 |
| Oxidation states | [-5, -2, -1, 1, 2, 3] | [-1, 1, 3, 5, 7] |
| Electronegativity (Pauling) | 1.62 | 2.2 |
| Electron affinity | 0.377 eV | 2.391 eV |
| Density | 1.180000e+4 kg/m³ | 7000 kg/m³ |
| Melting point | 303.85 °C | 301.85 °C |
| Boiling point | 1472.85 °C | -273.15 °C |
| Discovery year | 1861 | 1940 |