33As74.922
Metalloidp-block
Arsenic
Element 33 on the periodic table, symbol As, group 15, period 4.
Arsenic 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.
Appearance: metallic grey
Properties
- Atomic Number
- 33
- Atomic Mass
- 74.9216 u
- Group
- 15
- Period
- 4
- Block
- p-block
- Category
- Metalloid
- State at 25 °C
- Solid
- Melting Point
- Not measured
- Boiling Point
- Not measured
- Density
- 5.727 g/cm³
- Atomic Radius
- 115 pm
- Electronegativity
- 2.18
- Oxidation States
- -3, +3, +5
- Abundance in Crust
- 1.8 mg/kg
- Discovered
- 1250
- Discovered By
- Bronze Age
Electron Configuration
[Ar] 3d10 4s2 4p3
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3
Ionisation Energies (kJ/mol)
- 1. 947
- 2. 1,798
- 3. 2,735
- 4. 4,837
- 5. 6,043
- 6. 12,310
Elements near Arsenic
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.