Neptunium
Elemental State Np
Electron Configuration 1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p67s26d15f4
First Ionization Potential 6.266 eV
Electron Affinity  
Z*  
Pauling Electronegativity 1.3
Covalent Radius  
Metallic Radius 1.56 Å
Ionic Radius  
van der Waal's Radius  
Melting Point 644 oC
Boiling Point 3902 oC
Density 20.25 g/cm3
Other Properties All isotopes are radioactive

237Np half-life = 2.14×106 years