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Astatine,  85At
General properties
Name, seembol astatine, At
Pronunciation /ˈæstətn/ AS-tə-teen
or /ˈæstətɪn/ AS-tə-tin
Appearance unkent, but probably metallic
Astatine in the periodic cairt
Hydrogen (diatomic nonmetal)
Helium (noble gas)
Lithium (alkali metal)
Beryllium (alkaline yird metal)
Boron (metalloid)
Carbon (polyatomic nonmetal)
Nitrogen (diatomic nonmetal)
Oxygen (diatomic nonmetal)
Fluorine (diatomic nonmetal)
Neon (noble gas)
Sodium (alkali metal)
Magnesium (alkaline yird metal)
Aluminium (post-transeetion metal)
Silicon (metalloid)
Phosphorus (polyatomic nonmetal)
Sulfur (polyatomic nonmetal)
Chlorine (diatomic nonmetal)
Argon (noble gas)
Potassium (alkali metal)
Calcium (alkaline yird metal)
Scandium (transeetion metal)
Titanium (transeetion metal)
Vanadium (transeetion metal)
Chromium (transeetion metal)
Manganese (transeetion metal)
Iron (transeetion metal)
Cobalt (transeetion metal)
Nickel (transeetion metal)
Copper (transeetion metal)
Zinc (transeetion metal)
Gallium (post-transeetion metal)
Germanium (metalloid)
Arsenic (metalloid)
Selenium (polyatomic nonmetal)
Bromine (diatomic nonmetal)
Krypton (noble gas)
Rubidium (alkali metal)
Strontium (alkaline yird metal)
Yttrium (transeetion metal)
Zirconium (transeetion metal)
Niobium (transeetion metal)
Molybdenum (transeetion metal)
Technetium (transeetion metal)
Ruthenium (transeetion metal)
Rhodium (transeetion metal)
Palladium (transeetion metal)
Silver (transeetion metal)
Cadmium (transeetion metal)
Indium (post-transeetion metal)
Tin (post-transeetion metal)
Antimony (metalloid)
Tellurium (metalloid)
Iodine (diatomic nonmetal)
Xenon (noble gas)
Caesium (alkali metal)
Barium (alkaline yird metal)
Lanthanum (lanthanide)
Cerium (lanthanide)
Praseodymium (lanthanide)
Neodymium (lanthanide)
Promethium (lanthanide)
Samarium (lanthanide)
Europium (lanthanide)
Gadolinium (lanthanide)
Terbium (lanthanide)
Dysprosium (lanthanide)
Holmium (lanthanide)
Erbium (lanthanide)
Thulium (lanthanide)
Ytterbium (lanthanide)
Lutetium (lanthanide)
Hafnium (transeetion metal)
Tantalum (transeetion metal)
Tungsten (transeetion metal)
Rhenium (transeetion metal)
Osmium (transeetion metal)
Iridium (transeetion metal)
Platinum (transeetion metal)
Gold (transeetion metal)
Mercury (transeetion metal)
Thallium (post-transeetion metal)
Lead (post-transeetion metal)
Bismuth (post-transeetion metal)
Polonium (post-transeetion metal)
Astatine (metalloid)
Radon (noble gas)
Francium (alkali metal)
Radium (alkaline yird metal)
Actinium (actinide)
Thorium (actinide)
Protactinium (actinide)
Uranium (actinide)
Neptunium (actinide)
Plutonium (actinide)
Americium (actinide)
Curium (actinide)
Berkelium (actinide)
Californium (actinide)
Einsteinium (actinide)
Fermium (actinide)
Mendelevium (actinide)
Nobelium (actinide)
Lawrencium (actinide)
Rutherfordium (transeetion metal)
Dubnium (transeetion metal)
Seaborgium (transeetion metal)
Bohrium (transeetion metal)
Hassium (transeetion metal)
Meitnerium (unkent chemical properties)
Darmstadtium (unkent chemical properties)
Roentgenium (unkent chemical properties)
Copernicium (transeetion metal)
Ununtrium (unkent chemical properties)
Flerovium (post-transeetion metal)
Ununpentium (unkent chemical properties)
Livermorium (unkent chemical properties)
Ununseptium (unkent chemical properties)
Ununoctium (unkent chemical properties)


Atomic nummer 85
Staundart atomic wicht (Ar) (210)
Element category   metalloid, (disputit; sometimes classified as a halogen, mey be a metal)[1]
Group, block group 17 (halogens), p-block
Period period 6
Electron configuration [Xe] 4f14 5d10 6s2 6p5
per shell
2, 8, 18, 32, 18, 7
Pheesical properties
Phase solid
Meltin pynt 575 K ​(302 °C, ​576 °F)
Boilin pynt 610 K ​(337 °C, ​639 °F)
Density near r.t. (At2) 6.2–6.5 (predictit)[2] g/cm3
Heat o (At2) 54.39 kJ/mol
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
Thermal conductivity 1.7 W/(m·K)
CAS Registry Nummer 7440-68-8
Discovery Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940)
Maist stable isotopes
Main article: Isotopes o astatine
iso NA hauf-life DM DE (MeV) DP
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

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 certain hivier elements. Aw o its isotopes are short-lived; the maist stable is astatine-210, wi a hauf-life o 8.5 oors.[3] 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. Hermann, Andreas; Hoffmann, Roald; Ashcroft, N. W. (2013). "Condensed Astatine: Monatomic and Metallic". Physical Review Letters 111 (11). doi:10.1103/PhysRevLett.111.116404. 
  2. 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. 
  3. Price, Andy (2004-12-20). "Francium". Retrieved 2012-02-19.