Thallium vs Fermium
| Property | Tl Thallium | Fm Fermium |
|---|---|---|
| Atomic number | 81 | 100 |
| Symbol | Tl | Fm |
| Name | Thallium | Fermium |
| Category | post-transition-metal | actinide |
| Standard Atomic Weight | 204.3835 u | 257 u |
| Period | 6 | 7 |
| Group | 13 | N/A |
| Block | p | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f145d106p1 | [Rn] 5f12 7s2 |
| Oxidation states | [-5, -2, -1, 1, 2, 3] | [2, 3] |
| Electronegativity (Pauling) | 1.62 | 1.3 |
| Electron affinity | 0.377 eV | 0.339 eV |
| Density | 1.180000e+4 kg/m³ | 9700 kg/m³ |
| Melting point | 303.85 °C | 1526.85 °C |
| Boiling point | 1472.85 °C | -273.15 °C |
| Discovery year | 1861 | 1952 |