33 As
Metalloid
Arsenic
Famously toxic.
Properties of Arsenic
- Atomic number (Z)
- 33
- Symbol
- As
- Atomic mass
- 74.922 g/mol
- Category
- Metalloid
- Group
- 15
- Period
- 4
- Electron configuration
- [Ar] 3d¹⁰ 4s² 4p³
- Electronegativity (Pauling)
- 2.18
- Atomic radius
- 114 pm
- First ionization energy
- 947 kJ/mol
- Melting point
- 1090 K (816.9 °C)
- Boiling point
- 887 K (613.9 °C)
- Density
- 5.776 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Known since ancient times