Element Selenium (Se)

Atomic number 34 · nonmetal · Atomic mass 78.971 u

Atomic Mass
78.9710 u
Element Properties
Atomic Number 34
Atomic Mass 78.9710 u
Category nonmetal / 非金属
Group 16
Period 4
Block P
Electron Configuration [Ar] 3d¹⁰ 4s² 4p⁴
Electronegativity (Pauling) 2.55
Phase at STP Solid
Density 4.81 g/cm³
Year Discovered 1817

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