Neptunium
Atomic number
93
Atomic weight
237
Discovery (year)
1940
Atomic radius (A)
1.31，1.48
Melting point (
o
C)
Boiling point (
o
C)
Density (g/cm
3
)
Specific heat (cal/g
o
C)
Ionization potential (eV)
Electron Affinity (eV)
