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93
Np
[237]
Neptunium
Actinides · Group 7 · Period 6–7 (f)
Atomic properties
| Atomic number | 93 |
|---|---|
| Symbol | Np |
| Standard atomic weight | [237] |
| Classification | Actinides |
| Group | f-block series |
| Period | 7 |
| Block | f-block (actinide) |
| Electron configuration | [Rn] 5f4 6d1 7s2 |
| Electronegativity (Pauling) | 1.36 |
| Common oxidation states | +5, +4 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 20.45 g/cm³ |
| Melting point | 639 °C |
| Boiling point | 4000 °C |
| Discovered | 1940 |
| CAS number | — |