Arsenic (As)

From Wikipedia, the free encyclopediaArsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. Arsenic is a metalloid.

Arsenic in the periodic table

SymbolAs
Atomic number33
Group15
Period4
Blockp
Element categoryMetalloid

Physical properties

Phase at STPSolid
Density5.727 g/cm3
Atomic weight74.9216 u
Melting point K
°C
°F
Boiling point K
°C
°F

Atomära egenskaper

Electronegativity (Pauling Scale)2.18
Electron affinity77.65 kJ/mol
Ionization energies
1947 kJ/mol
2 1798 kJ/mol
3 2735 kJ/mol
4 4837 kJ/mol
5 6043 kJ/mol
6 12310 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3
Electrons per shell2, 8, 18, 5

History

Discovered815
Discovered byMiddle-Eastern alchemists