Neptunium (Np)
Neptunium (Np) is element 93, an actinide. Atomic mass 237, configuration [Rn] 5f⁴ 6d¹ 7s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 93 |
|---|---|
| Symbol | Np |
| Standard atomic weight | 237 |
| Category | Actinide |
| Period | 7 |
| State at room temperature | Solid |
| Electron configuration | [Rn] 5f⁴ 6d¹ 7s² |
| Valence electrons | 2 (Variable) |
| Common oxidation states | +5 |
| Common ions | No common ions |
| Electronegativity (Pauling) | 1.3 |
| First ionization energy | 605 kJ/mol |
| Atomic radius | 175 pm |
| Density | 20.2 g/cm³ |
| Melting point | 640°C |
| Boiling point | 3902°C |
Common uses
- Precursor to Pu-238 production; Neutron detectors
Where it matters
- First transuranic element
Hazards
- Radioactive
History
| Discovered | 1940 |
|---|---|
| Discovered by | McMillan & Abelson |
| Name | Planet Neptune |