← Back to the periodic table
85
At
[210]
Astatine
Halogens · Group 17 · Period 6
Atomic properties
| Atomic number | 85 |
|---|---|
| Symbol | At |
| Standard atomic weight | [210] |
| Classification | Halogens |
| Group | 17 |
| Period | 6 |
| Block | p-block |
| Electron configuration | [Xe] 4f14 5d10 6s2 6p5 |
| Electronegativity (Pauling) | 2.20 |
| Common oxidation states | +1, -1 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 7 g/cm³ |
| Melting point | 302 °C |
| Boiling point | 337 °C |
| Discovered | 1940 |
| CAS number | — |