NO. 033Metalloid
As
Arsenic
Arsenic is a toxic metalloid historically used in poisons and now in semiconductors and pesticides.
Technical Specifications
Atomic Mass74.92 u
Density5.73 g/cm³
Melting Point1090 K
Boiling Point887 K
Atomic Radius114 pm
Electronegativity2.18
Ionization Energy947 kJ/mol
Electron Affinity78 kJ/mol
Bonding TypeCovalent
Oxidation States-3, 3, 5
Acid/BaseCan act as acid or base
ReactivityMedium
Electron Configuration
[Ar] 3d10 4s2 4p3
Discovered ByAncient civilizations
Year-1250
Known Isotopes
As-75