Astatine

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Astatine,  85At
General properties
Appearance unkent, but probably metallic
Mass nummer 210 (most stable isotope)
Astatine in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
I

At

Uus
poloniumastatineradon
Atomic nummer (Z) 85
Group group 17 (halogens)
Period period 6
Element category   metalloid
Block p-block
Electron confeeguration [Xe] 4f14 5d10 6s2 6p5
Electrons per shell
2, 8, 18, 32, 18, 7
Pheesical properties
Phase (at STP) solit
Meltin pynt 575 K ​(302 °C, ​576 °F)
Bylin pynt 610 K ​(337 °C, ​639 °F)
Density (near r.t.) (At2) 6.2–6.5 (predictit)[1] g/cm3
Heat o vapourisation (At2) 54.39 kJ/mol
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 361 392 429 475 531 607
Atomic properties
Oxidation states −1, +1, +3, +5, +7
Electronegativity Pauling scale: 2.2
Covalent radius 150 pm
Van der Waals radius 202 pm
Miscellanea
Thermal conductivity 1.7 W/(m·K)
CAS Nummer 7440-68-8
History
Diskivery Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940)
Main isotopes o astatine
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
209At syn 5.41 h β+ 3.486 209Po
α 5.758 205Bi
210At syn 8.1 h β+ 3.981 210Po
α 5.632 206Bi
211At syn 7.21 h ε 0.786 211Po
α 5.983 207Bi
| references | in Wikidata

Astatine is a radioactive chemical element wi the chemical seembol At an atomic nummer 85. It occurs on Yird anly as the result o the radioactive decay o certaint hivier elements. Aw o its isotopes are short-lived; the maist stable is astatine-210, wi a hauf-life o 8.5 oors.[4] Accordinly, much less is kent aboot astatine nor maist ither elements. The observed properties are consistent wi it bein a hivier analog o iodine; mony ither properties hae been estimatit based on this resemblance.

References[eedit | eedit soorce]

  1. Bonchev, Danail; Kamenska, Verginia (1981). "Predicting the properties of the 113–120 transactinide elements". The Journal of Physical Chemistry. ACS Publications. 85 (9): 1177–86. doi:10.1021/j150609a021. 
  2. Hermann, Andreas; Hoffmann, Roald; Ashcroft, N. W. (2013). "Condensed Astatine: Monatomic and Metallic". Physical Review Letters. 111 (11). doi:10.1103/PhysRevLett.111.116404. 
  3. Rothe, S.; Andreyev, A. N.; Antalic, S.; Borschevsky, A.; Capponi, L.; Cocolios, T. E.; De Witte, H.; Eliav, E.; et al. (2013). "Measurement of the first ionization potential of astatine by laser ionization spectroscopy". Nature Communications. 4: 1835–. doi:10.1038/ncomms2819. PMC 3674244Freely accessible. PMID 23673620. 
  4. Price, Andy (2004-12-20). "Francium". Retrieved 2012-02-19.