33 As Arsenic 74.922
Metalloid
Arsenic 砷
[Ar] 3d¹⁰ 4s² 4p³
- Period 4
- Group 15
- Block p
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³
Orbital diagram (valence)
- Electrons per shell
- 2, 8, 18, 5
- Unpaired electrons
- 3
- Zeff (Slater)
- 6.30
Properties
- Atomic weight
- 74.922
- Electronegativity (Pauling)
- 2.18
- First ionization energy
- 947 kJ/mol
- Electron affinity
- 78.15 kJ/mol
- Covalent radius
- 119 pm
- van der Waals radius
- 185 pm
- Melting point
- 1090 K
- Boiling point
- 887 K
- Density
- 5.776 g/cm³
- Melting / boiling point
- 816.9 °C / 613.9 °C
- Common oxidation states
- +5, +3, −3
- Discovered
- Known since antiquity
Arsenic in the course
The lessons that discuss this element most (ranked by mentions).
Lab experiments with Arsenic
Periodic trend
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).