Arsenic

Document v1 · published by Koskamo · updated 2026-10-04

Arsenic (As) is chemical element 33, a metalloid in group 15, period 4 (PubChem).

Atomic number: 33
Symbol: As
Group: 15
Period: 4
Atomic mass: 74.92159 u
Electron configuration: [Ar]4s2 3d10 4p3
Electronegativity (Pauling scale): 2.18
Atomic radius (van der Waals): 185 pm
Ionization energy: 9.815 eV
Electron affinity: 0.81 eV
Oxidation states: +5, +3, -3
Standard state: Solid
Melting point: 1090 K
Boiling point: 887 K
Density: 5.776 g/cm³
Chemical group: Metalloid
Year discovered: Ancient

Source and provenance

Original source: pubchem.ncbi.nlm.nih.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: PubChem periodic table data (NIH/NLM, pubchem.ncbi.nlm.nih.gov/ptable); group and period from Jefferson Lab via PubChem

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Version history

Published by Koskamo2026-10-04
Version 1