Arsenic (As) - Element 33 | Properties & Electron Configuration
What is Arsenic?
Arsenic (As) is element 33, a metalloid in period 4, group 15. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³.
| Atomic Number | 33 |
| Symbol | As |
| Atomic Mass | 74.922 u |
| Category | Metalloid |
| Period | 4 |
| Group | 15 |
| Block | p |
| Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³ |
| Short Config | [Ar] 3d¹⁰ 4s² 4p³ |
| Electronegativity | 2.18 |
| Atomic Radius | 119 pm |
| Ionization Energy | 947 kJ/mol |
| Electron Affinity | 78 kJ/mol |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Arsenic is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³. In noble gas shorthand, this is written as [Ar] 3d¹⁰ 4s² 4p³.
Arsenic is a p-block element in group 15, period 4.
Periodic Trends
Electronegativity: Arsenic has a Pauling electronegativity of 2.18. Within group 15, electronegativity generally decreases down the group.
Atomic Radius: 119 pm. Across period 4, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 947 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Arsenic on the Interactive Periodic TableRelated Topics
Nitrogen (N)
Properties of Nitrogen - same group as Arsenic
Phosphorus (P)
Properties of Phosphorus - same group as Arsenic
Antimony (Sb)
Properties of Antimony - same group as Arsenic
Potassium (K)
Properties of Potassium - same period as Arsenic
Calcium (Ca)
Properties of Calcium - same period as Arsenic
Scandium (Sc)
Properties of Scandium - same period as Arsenic