Beryllium vs Roentgenium
| Property | Be Beryllium | Rg Roentgenium |
|---|---|---|
| Atomic number | 4 | 111 |
| Symbol | Be | Rg |
| Name | Beryllium | Roentgenium |
| Category | alkaline-earth-metal | transition-metal |
| Standard Atomic Weight | 9.012183 u | 281 u |
| Period | 2 | 7 |
| Group | 2 | 11 |
| Block | s | s |
| Phase at STP | solid | N/A |
| Electron configuration | [He]2s2 | [Rn] 7s2 5f14 6d9(predicted) |
| Oxidation states | [0, 1, 2] | [-1, 1, 3, 5] |
| Electronegativity (Pauling) | 1.57 | N/A |
| Electron affinity | -0.52 eV | 1.6 eV |
| Density | 1850 kg/m³ | 2.870000e+4 kg/m³ |
| Melting point | 1286.85 °C | -273.15 °C |
| Boiling point | 2470.85 °C | -273.15 °C |
| Discovery year | 1797 | 1994 |