94 neptunium ← plutonium → americium Sm ↑ Pu ↓ (Uqq) periodic table General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [ Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r.t.) 19.816 g/cm³ Liquid density at m.p.
