93Np

Neptunium

Actinide

Neptunium (Np) is element 93, an actinide, in period 7 of the periodic table. Its atomic mass is usually given as 237, it melts at 644 °C and boils at 3902 °C. Discovered by Edwin McMillan, 1940.

Atomic Number93

SymbolNp

NameNeptunium

Atomic Weight237 u

CategoryActinide

Period7

Melting Point644 °C

Boiling Point3902 °C

Density20.45 g/cm³

Electron Config[Rn] 5f4 6d1 7s2

Discovered ByEdwin McMillan, 1940

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