33As

Arsenic

Metalloid

Arsenic (As) is element 33, a metalloid, in period 4 and group 15 of the periodic table. Its standard atomic weight is 74.922, it melts at 817 °C and boils at 614 °C. It has been known since antiquity.

Atomic Number33

SymbolAs

NameArsenic

Atomic Weight74.922 u

CategoryMetalloid

Period4

Group15

Melting Point817 °C

Boiling Point614 °C

Density5.776 g/cm³

Electron Config[Ar] 3d10 4s2 4p3

Discovered ByKnown since antiquity

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