Astatine (At) — Element 85: Properties & Data | Aladdin Scientific
Astatine(At) — Element 85
Astatine (At) is a halogen with atomic number 85 and atomic mass 209.987. It has melting point 575 K (302 °C), density 7 g/cm³. It sits in group 17 and period 6 of the periodic table and was discovered in 1940.
Key facts
| Atomic mass | 209.9872 u |
|---|---|
| Electron configuration | [Xe]6s2 4f14 5d10 6p5 |
| Oxidation states | 7, 5, 3, 1, -1 |
| Electronegativity (Pauling) | 2.2 |
| Atomic radius (van der Waals) | 202 pm |
| Ionization energy | 9.5 eV |
| Electron affinity | 2.8 eV |
| Melting point | 575 K |
| Density | 7 g/cm³ |
| Standard state | Solid |
| Year discovered | 1940 |
Frequently asked questions
What is the electron configuration of astatine?
The ground-state electron configuration of astatine is [Xe]6s2 4f14 5d10 6p5.
What group and period is astatine in?
Astatine (At) is in group 17 and period 6 of the periodic table, classified as a halogen.
What is the melting point of astatine?
Astatine melts at 575 K (302 °C).
What is the standard state of astatine?
Astatine is a solid at standard temperature and pressure.
Related elements
About this data: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .