PhysLink.com Logo
Black Friday Sale 2017 - Educational Gifts and Toys
Black Friday Sale 2017 - Educational Gifts and Toys

At - Astatine

Astatine

 Astatine 
At
Atomic Number: 85
Atomic Weight: -210.0
Element Type: Halogen
Crystal Structure:
Melting Point: 302.0°C = 575.6°F = 575.15 K
Boiling Point: °C = °F = K
Critical Temp: °C = °F = K
Atomic Radius: 1.43 Å (Å = Angstrom = 10-10 m)
Covalent Radius: 1.45 Å
Electronegativity: 2.2

History

(Gr. astatos, unstable) Synthesized in 1940 by D.R. Corson, K.R. MacKenzie, and E.Segre at the University of California by bombarding bismuth with alpha particles. Thelongest-lived isotopes, with naturally occurring uranium and thorium isotopes, and tracesof 217At are equilibrium with 233U and 239Np resulting from integration of thorium anduranium with naturally produced neutrons. The total amount of astatine present in theearth's crust, however, is less than 1 oz.


Sources


Science Quote

'The mathematician's patterns, like the painter's or the poets, must be beautiful; the ideas, like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics.'

Godfrey Hardy
(1877-1947)


All rights reserved. © Copyright '1995-'2017 PhysLink.com