| Atomic Number: | 93 |
| Element Symbol: | Np |
| Element Name: | Neptunium |
| Atomic Weight: | 237 |
| Group Name: | Actinoid |
| Period Number: | 7 (actinoid) |
| Block: | f-block |
| Ground State Configuration: | [Rn] 5f4 6d 7s2 |
| Ground State Level: | 6L11/2 |
| Standard State: | Artificially prepared |
| Bond Length: | 262 |
| Atomic Radius Empirical: | 175 |
| First Ionization Energy: | 604.5 |
| Pauling Electronegativity: | 1.36 |
| Allred Rochow Electronegativity: | 1.22 |
| Density Of Solid: | 20450 |
| Molar Volume: | 11.59 |
| Electrical Resistivity: | 120 |
| Melting Point: | 637 |
| Boiling Point: | 4000 |
| Thermal Conductivity: | 6 |
| Enthalpy Of Fusion: | 10 |
| Enthalpy Of Vaporization: | 335 |
| Most Common Oxidation Numbers: | 5 |
| Color: | Silvery metallic |
| Classification: | Metallic |
| Discovered By: | Edwin M. McMillan and P. H. Abelson |
| Discovered At: | USA |
| Discovered When: | 1940 |
| Origin Of Name: | Named after the planet Neptune |
Calculate the molecular weight of Neptunium or molecular weight Np.
Also see the full list of chemical elements and atomic weights.