Other

Astat (At) - Properties


Atomic mass, symbol and atomic number

astatine is a naturally occurring element with the element symbol At and the ordinal number 85. In the periodic table it stands with an atomic mass of 209.987 u in the 7th main group. The chemical element discovered by Corson, MacKenzie and Segrè in 1940 is radioactive and is in a solid state of aggregation at room temperature.

Characteristics: Astat (English Astatine)

General
Chemical element:astatine
Symbol:At
Atomic number:85
Group:halogen group
Period:6
Block:p-block
Series:halogens
Appearance:silver
explorers:D. Corson, K. MacKenzie and E. Segrè
Year of discovery:1940
Atomic properties
Atomic mass:209.987 u
Atomic radius:150 pm
Covalent radius:202 pm
Van der Waals radius:216 pm
Electron configuration:Xe 4f14 5d10 6s2 6p5
ionization:920 kJ / mol
Physical Properties
Physical state:firmly
Density:???
Crystal structure:unknown
Magnetism:unknown
molar volume:unknown
Mohs hardness:/
Melting point:302 ° C
Boiling point:337 ° C
Heat of fusion:36 kJ / mol
Heat of vaporization:8 kJ / mol
Thermal conductivity:2 W
Chemical properties
electronegativity:2,2

Did you know that ...

  • Astat is the rarest element on earth?
  • the longest-lived isotope of Astat only has a half-life of about eight hours?
  • the production of artificial Astat is cheaper than to naturally degrade it?
  • Astatine is used for the irradiation of tumors?