| Name | neptunium |
|---|---|
| Symbol | Np |
| Atomic Weight | 237.05 |
| Atomic Number | 93 |
| CAS ID | 7439-99-8 |
| Group Number | |
| Group Name | Actinoid |
| Period Number | 7 |
| Origin of Name | Named after the planet Neptune. |
| Year Discovered | 1940 |
| Discovery Credits | E. M. McMillan and P. Abelson at Berkeley, California, USA. |
| Class | Metallic |
| Color | Silvery Metallic |
| Standard State | Solid at 77 F & 298 K |
| Description | Radioactive silvery metal which does not occur naturally. Attacked by oxygen, steam, and acids, but not alkalis. |