85
210.00
At
Astatine
Identification
CAS Number: 7440-68-8
Discovery Year: 1940
Discoverer: D.R.Corson, K.R.MacKenzie, E.Segré
Discovery Location: United States
Properties
Atomic Dimensions
Thermodynamics
Electronic Structure
Electron Config: [Xe] 4f14 5d10 6s2 6p5
Block: p
Period: 6 →Group: 17 →Electronegativity: 2.2 →Electron Affinity: 2.8 eV →Oxidation States: -1, +1, +3, +5, +7
Abundance & Geochemistry
Geochemical Class: U/Th decay series
Goldschmidt Class: synthetic
About
Radioactive halogen element. Occurs naturally from uranium and thorium decay. At least 20 known isotopes. At-210, the most stable, has a half-life of 8.3 hours. Synthesized by nuclear bombardment in 1940 by D.R. Corson, K.R. MacKenzie and E. Segre at the University of California.
Isotopes
At-210 210 ☢ 8.10 h
At-211 211 ☢ 7.21 h
