Astatine



85 radon
Uus)
General
Number astatine, At, 85
halogens
Block p
Appearance metallic (presumed)
Standard atomic weight (210)  g·mol−1
Xe] 4f14 5d10 6s² 6p5
shell 2, 8, 18, 32, 18, 7
Physical properties
Phase solid
F)
F)
kJ·mol−1
Vapor pressure
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 361 392 429 475 531 607
Atomic properties
Crystal structure no data
Oxidation states ±1, 3, 5, 7
Electronegativity 2.2 (Pauling scale)
Ionization energies 1st: 890±40 kJ/mol
Miscellaneous
Magnetic ordering no data
Thermal conductivity (300 K) 1.7  W·m−1·K−1
CAS registry number 7440-68-8
Selected isotopes
Main article: Isotopes of astatine
iso NA half-life DM DE (MeV) DP
210At 100% 8.1 h β+ 3.981 210Po
α 5.631 206Bi
References

Astatine (halogens.

Notable characteristics

This highly lead.

Astatine is the rarest naturally-occurring element, with the total amount in Earth's crust estimated to be less than 1 oz (28 g) at any given time; this amounts to less than one teaspoon of the element. Guinness World Records has dubbed the element the rarest on Earth, stating: "Only around 0.9 oz (25 g) of the element astatine (At) occurring naturally"; Isaac Asimov, in a 1957 essay on large numbers, scientific notation, and the size of the atom, wrote that in "all of North and South America to a depth of ten miles", the number of astatine atoms at any time was "only a trillion".[2]

History

The existence of "eka-iodine" had been predicted by alpha particles. An earlier name for the element was alabamine (Ab).

Occurrence

Astatine is produced by bombarding distilled from the target by heating in the presence of air.

Compounds

Multiple nuclear medicine.[1]

Isotopes

Main article: isotopes of astatine

Astatine has 33 known nanoseconds.

References

  1. ^ http://periodic.lanl.gov/elements/85.html
  2. ^ http://ia331335.us.archive.org/1/items/onlyatrillion017765mbp/onlyatrillion017765mbp_djvu.txt
  • Los Alamos National Laboratory - Astatine


 v • d • e chemical elements

Hydrogen H2 | Nitrogen N2 | Oxygen O2 | Fluorine F2 | Chlorine Cl2 | Bromine Br2 | Iodine I2 | Astatine At2

 
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