| name | Neptunium |
| latin | Neptunium |
| french | Neptunium |
| german | Neptunium |
| symbol | Np |
| proton number | 93 |
| atomic weight | 237.0482 |
| Pauling electronegativity | 1.36 |
| electronic configuration | [Rn] 5f46d17s2 1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p65f46d17s2 |
| melting point | 910 K, 637°C, 1178°F |
| boiling point | 4273 K, 4000°C, 7232°F |
| group | - |
| period | 7 |
| state (by 20°C) | solid |
| oxidation states | +3, +4, +5, +6 |
| Year of discovery | Discoverers |
| 1940 | Edwin M. McMillan (1907-1991) P. H. Abelson |