85 · At
Astatine
Produced in the Berkeley cyclotron in 1940.
Identity
- Atomic number
- 85
- Symbol
- At
- Canonical name
- Astatine
- Category
- halogen
- Group
- 17
- Period
- 6
- Block
- p
Placed with the halogens by its column. Whether it is a metalloid remains discussed.
Properties
These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.
- Atomic mass
- [210] No standard atomic weight. The number shown is the conventional mass number used in tables, not a measured mass in u.
- Electron configuration
- [Xe] 4f14 5d10 6s2 6p5
- Electrons per shell
- 2, 8, 18, 32, 18, 7
- Standard state
- solid
- Density
- 6.35 g/cm³
- Melting point
- 575 K
- Boiling point
- 610 K
- Electronegativity
- 2.2 Pauling
- First ionization energy
- 899.003 kJ/mol
- Electron affinity
- 233 kJ/mol
Notable isotopes
This summary is not an inventory of every isotope.
Conventional mass number: 210
History
Astatine at the cyclotron
Synthesis · confirmed · 1940
Corson, MacKenzie, and Segrè produce astatine by bombarding bismuth.
- Target
- 209Bi
- Projectile
- 4He
- Instrument
- Berkeley cyclotron
Etymology
- Theme
- property
- Language
- grec
- Root
- astatos
- Meaning
- unstable
Scientists
Places and institutions
- Berkeley — historical setting : United States — present country : United States
See also
Sources
- IUPAC, Periodic Table of the Elements
- Bowserinator, Periodic Table JSON. Compilation secondaire d’où viennent les grandeurs physiques importées (masse, densité, températures, énergies). Elles ne sont pas revérifiées une à une auprès du NIST ou de la CIAAW.
- IUPAC, décisions sur la priorité et les noms des éléments transfermiens (1997–2016)