Astatine (At): Atomic number: 85, Atomic mass: (210) g.mol -1, Electronegativity: 2.2, Density: unknown, Melting point: 302 °C, Boiling point: 337 °C (estimation), Vanderwaals radius: unknown, Ionic radius: unknown, Isotopes: 7, Electronic shell: [ Xe ] 4f14 5d10 6s2 6p5, Energy of first ionisation: (926) kJ.mol -1, Discovered by: D.R. Corson 1940. Astatine is a highly radioactive element and it is the heaviest known halogen. Its chemical properties are believed to be similar to those of iodine. Is has been little researched because all its isotopes have short half lives. All that is known about the element has been estimated from knowing its position in the periodic table below iodine and by studying its chemistry in extreme diluted solutions. Applications: Astatine is never encountered outside nuclear facilities or research laboratories. Astatine in the environment: Total world production of astatine to date is estimated to be less than a millionth of a gram, and virtually all of this has now decayed away.

 

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Astatine (At): Atomic number: 85, Atomic mass: (210) g.mol -1, Electronegativity: 2.2, Density: unknown, Melting point: 302 °C, Boiling point: 337 °C (estimation), Vanderwaals radius: unknown, Ionic radius . . . View Full Definition

Halogen: An element of group VIIA (a. k. a. Group 18). The name means 'salt former'; halogens react with metals to form binary ionic compounds. Fluorine (F), chlorine (Cl), bromine (Br), iodine (I), . . . View Full Definition