Neptunium vs Meitnerium
| Property | Np Neptunium | Mt Meitnerium |
|---|---|---|
| Atomic number | 93 | 109 |
| Symbol | Np | Mt |
| Name | Neptunium | Meitnerium |
| Category | actinide | transition-metal |
| Standard Atomic Weight | 237 u | 278 u |
| Period | 7 | 7 |
| Group | N/A | 9 |
| Block | s | s |
| Phase at STP | solid | N/A |
| Electron configuration | [Rn]7s25f46d1 | [Rn]7s25f146d7(calculated) |
| Oxidation states | [2, 3, 4, 5, 6, 7] | [1, 3, 4, 6, 8, 9] |
| Electronegativity (Pauling) | 1.36 | N/A |
| Electron affinity | 0.48 eV | 1.7 eV |
| Density | 2.025000e+4 kg/m³ | 3.740000e+4 kg/m³ |
| Melting point | 643.85 °C | -273.15 °C |
| Boiling point | 3901.85 °C | -273.15 °C |
| Discovery year | 1940 | 1982 |