Astatine (At) - Element 85 | Properties & Electron Configuration
What is Astatine?
Astatine (At) is element 85, a halogen in period 6, group 17. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁵.
| Atomic Number | 85 |
| Symbol | At |
| Atomic Mass | 210 u |
| Category | Halogen |
| Period | 6 |
| Group | 17 |
| Block | p |
| Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁵ |
| Short Config | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵ |
| Electronegativity | 2.2 |
| Atomic Radius | N/A |
| Ionization Energy | 920 kJ/mol |
| Electron Affinity | 270 kJ/mol |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Astatine is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁵. In noble gas shorthand, this is written as [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵.
Astatine is a p-block element in group 17, period 6.
Periodic Trends
Electronegativity: Astatine has a Pauling electronegativity of 2.2. Within group 17, electronegativity generally decreases down the group.
Ionization Energy: 920 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 Astatine on the Interactive Periodic TableRelated Topics
Fluorine (F)
Properties of Fluorine - same group as Astatine
Chlorine (Cl)
Properties of Chlorine - same group as Astatine
Bromine (Br)
Properties of Bromine - same group as Astatine
Cesium (Cs)
Properties of Cesium - same period as Astatine
Barium (Ba)
Properties of Barium - same period as Astatine
Lanthanum (La)
Properties of Lanthanum - same period as Astatine