93 – Np – Neptunium

Np-237 (half life 2.14 million years) is produced by nuclear reactions in U-238, so traces of Neptunium exist in the pitchblende shown here. Amount: 0.4 g pitchblende, corresponding to 47 fg or 120 million atoms of Np-237.

Physical and chemical data
Atomic mass	237.0482
Density	20.48 g·cm^-3
Melting point	639 °C
Boiling point	3902 °C
Abundance	4.00e-17 %
Electronegativy	1.2
Oxydation levels	6, [5], 4, 3
Electron configuration	[Rn]5f4 6d 7s2