Key information
Atomic number: 
85
Atomic weight: 
209.99
Specific heat capacity: 
0 J/kg/K
Group: 
Halogen Elements

The chemical symbol for Astatine is At. There are about 20 isotopes known, all of which are radioactive. The longest-lived isotope, has a half-life of only 8.3 hours.

Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages