85At210
Astatine
Halogen · element 85 · group 17, period 6
Quick facts
| Symbol | At |
|---|---|
| Atomic number | 85 |
| Relative atomic mass | 210 |
| Category | Halogen |
| Position | group 17, period 6 |
| State at 20 °C | Solid |
| Melting point | 302 °C |
| Boiling point | 337 °C |
| Density | — |
| Electronegativity | 2.2 |
| Electron configuration | [Xe] 4f14 5d10 6s2 6p5 |
About Astatine
Astatine has the symbol At and atomic number 85, which means every astatine atom has 85 protons in its nucleus and, in a neutral atom, 85 electrons. At room temperature it is a solid.
Halogens are in group 7. They have 7 outer electrons, exist as diatomic molecules (like Cl₂), and get less reactive going down the group.
It melts at 302 °C and boils at 337 °C.
Explore it
See where astatine sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.