Neptunium

General properties
Name, symbol, number	neptunium, Np, 93
Element category	actinide
Group, period, block	n/a, 7, f
Standard atomic weight	(237)
Electron configuration	[Rn] 5f4 6d1 7s2 2, 8, 18, 32, 22, 9, 2
History
Discovery	Edwin McMillan and Philip H. Abelson (1940)

Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive metal, neptunium is the first transuranic element, and belongs to the actinide series. Its most stable isotope, ²³⁷Np, is a by-product of nuclear reactors and plutonium production, and it can be used as a component in neutron detection equipment. Neptunium is also found in trace amounts in uranium ores due to transmutation reactions.

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