Mendelevium vs Roentgenium
| Property | Md Mendelevium | Rg Roentgenium |
|---|---|---|
| Atomic number | 101 | 111 |
| Symbol | Md | Rg |
| Name | Mendelevium | Roentgenium |
| Category | actinide | transition-metal |
| Standard Atomic Weight | 258 u | 281 u |
| Period | 7 | 7 |
| Group | N/A | 11 |
| Block | s | s |
| Phase at STP | solid | N/A |
| Electron configuration | [Rn]7s25f13 | [Rn] 7s2 5f14 6d9(predicted) |
| Oxidation states | [2, 3] | [-1, 1, 3, 5] |
| Electronegativity (Pauling) | 1.3 | N/A |
| Electron affinity | 0.997 eV | 1.6 eV |
| Density | 1.030000e+4 kg/m³ | 2.870000e+4 kg/m³ |
| Melting point | 826.85 °C | -273.15 °C |
| Boiling point | -273.15 °C | -273.15 °C |
| Discovery year | 1955 | 1994 |