Arsenic

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Symbol:

As

Atomic Number:

33

Relative Atomic Mass:

74.92160 g mol^-1

Natural Abundance in Lithosphere, hydrosphere and atmosphere:

6 x 10^-4% (mass fraction)

Electron Configuration:

[Ar]3d¹⁰4s²4p³

Oxidation States:

V, III, -III

Atomic Radius:

124.5pm

Covalent Radius:

121pm

Ionic Radius:

34pm (for +5 oxidation state)

58pm (for +3 oxidation state)

Melting Point:

613°C

Density:

5.72 g cm^-3 (at 20°C)

First Ionisation Energy:

9.81 eV

Reduction Potential:

0.234V

for AsO_3/2 + 3H⁺ +3e^- a As_(s) + 3/2H₂O

Electronegativity (Allred and Rochow):

2.2

Number of Natural Isotopes:

1

Mass Number of the Most Abundant Isotopes:

75 g mol^-1 a 100% abundance