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 | |||||||||||||
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Symbol | As | ||||||||||||
Atomic number | 33 | ||||||||||||
Group | 15 | ||||||||||||
Period | 4 | ||||||||||||
Block | p | ||||||||||||
Element category | Metalloid | ||||||||||||
Physical properties | |||||||||||||
Phase at STP | Solid | ||||||||||||
Density | 5.727 g/cm3 | ||||||||||||
Atomic weight | 74.9216 u | ||||||||||||
Melting point | - | ||||||||||||
Boiling point | K °C °F | ||||||||||||
Atomic properties | |||||||||||||
Electronegativity (Pauling Scale) | 2.18 | ||||||||||||
Electron affinity | 77.65 kJ/mol | ||||||||||||
Oxidation states | −3, −2, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide) | ||||||||||||
Ionization energies |
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Electron configuration | |||||||||||||
Elektronkonfiguration (shorthand) | [Ar] 3d10 4s2 4p3 | ||||||||||||
Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3 | ||||||||||||
Electrons per shell | 2, 8, 18, 5 | ||||||||||||
History | |||||||||||||
Discovered | 815 | ||||||||||||
Discovered by | Middle-Eastern alchemists |