Quick answerArsenic (As) is a metalloid with atomic number 33 and an atomic mass of 74.922 (2023), in group 15, period 4. It was discovered by Albertus Magnus in 1250. It is used for semiconductor doping and wood preservatives. Its electron configuration is [Ar] 3d10 4s2 4p3.
Arsenic is a notorious poison that also dopes computer chips, preserves timber, and treats a rare form of leukaemia.
Key facts
| Symbol | As |
|---|---|
| Atomic number | 33 |
| Atomic mass | 74.922 (IUPAC standard atomic weight, 2023) |
| Category | metalloid |
| Group | 15 |
| Period | 4 |
| Block | p-block |
| Electron configuration | [Ar] 3d10 4s2 4p3 |
| Discovered | Albertus Magnus, 1250 |
| Uses | semiconductor doping, wood preservatives, leukaemia treatment, glass production, alloys |
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Keep exploring
- Periodic table — all 118 elements
- Boron (B) — another metalloid, atomic number 5
- Silicon (Si) — another metalloid, atomic number 14
- Germanium (Ge) — another metalloid, atomic number 32
- Antimony (Sb) — another metalloid, atomic number 51
- Tellurium (Te) — another metalloid, atomic number 52
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
- Wikipedia — Arsenic
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.