Neptunium (Np) - Element 93 | Properties & Electron Configuration
What is Neptunium?
Neptunium (Np) is element 93, a actinide in period 7. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁴ 6s² 6p⁶ 6d¹ 7s².
| Atomic Number | 93 |
| Symbol | Np |
| Atomic Mass | 237 u |
| Category | Actinide |
| Period | 7 |
| Group | N/A (f-block) |
| Block | f |
| Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁴ 6s² 6p⁶ 6d¹ 7s² |
| Short Config | [Rn] 5f⁴ 6d¹ 7s² |
| Electronegativity | 1.36 |
| Atomic Radius | 175 pm |
| Ionization Energy | 605 kJ/mol |
| Electron Affinity | N/A |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Neptunium is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁴ 6s² 6p⁶ 6d¹ 7s². In noble gas shorthand, this is written as [Rn] 5f⁴ 6d¹ 7s².
Neptunium is a f-block element, period 7.
Periodic Trends
Electronegativity: Neptunium has a Pauling electronegativity of 1.36.
Atomic Radius: 175 pm. Across period 7, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 605 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Neptunium on the Interactive Periodic Table