93
Np
237
Neptunium
Element 93 · 237 u · f-block
actinide
The first transuranium element discovered. Named after Neptune. A byproduct of nuclear reactors.
Phase (STP)
Solid
Melting Point
644 °C
Boiling Point
3902 °C
Density
20.45 g/cm³
Electronegativity
1.36
Atomic Radius
175 pm
Ionization Energy
605 kJ/mol
Electron Affinity
—
Discovered
1940 · Edwin McMillan
Electron Configuration
[Rn] 5f4 6d1 7s2
Electron Orbitals
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