33As74.922
Arsenic
MetalloidsIn-between elements with some metal and some non-metal properties. Many are semiconductors.
[Ar] 3d¹⁰ 4s² 4p³
- Atomic number
- 33
- Atomic mass
- 74.922
- Protons
- 33
- Neutrons
- 42 (most common)
- Electrons
- 33
- Shells
- 2, 8, 18, 5
- State at 25 °C
- Solid
- Position
- Group 15, period 4
Proton (+)Neutron (0)Electron (−)
Discovered byAlbertus Magnus, about 1250
Arsenic compounds were known in ancient times. Albertus Magnus is credited with first isolating the element.
Did you know?
- It is notoriously poisonous.
- Arsenic in drinking water is a serious health problem in parts of South Asia.
Where it's found
- Minerals like realgar
- Some groundwater, including parts of West Bengal
What it's used for
- Gallium arsenide chips
- Formerly wood preservatives and pesticides
Try it
There's no safe home experiment for Arsenic. Explore it with the animated atom above instead.