Francium

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Francium,  87Fr
General properties
Mass nummer223 (most stable isotope)
Francium 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 Gowd 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
Cs

Fr

(Uue)
radonfranciumradium
Atomic nummer (Z)87
Groupgroup 1 (alkali metals)
Periodperiod 7
Element category  alkali metal
Blocks-block
Electron confeeguration[Rn] 7s1
Electrons per shell
2, 8, 18, 32, 18, 8, 1
Pheesical properties
Phase (at STP)solit presumably
Meltin pynt? 300 K ​(27 °C, ​80 °F)
Bylin pynt? 950 K ​(677 °C, ​1250 °F)
Density (near r.t.)1.87 g/cm3 (extrapolatit)
Heat o fusionca. 2 kJ/mol
Heat o vapourisationca. 65 kJ/mol
Vapour pressur (extrapolatit)
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 404 454 519 608 738 946
Atomic properties
Oxidation states+1 ​(a strangly basic oxide)
ElectronegativityPauling scale: 0.7
Ionisation energies
  • 1st: 393[1] kJ/mol
Covalent radius260 pm (extrapolatit)
Van der Waals radius348 pm (extrapolatit)
Miscellanea
Creestal structur ​body-centred cubic
[[File:body-centred cubic|50px|alt=Body-centred cubic creestal structur for francium|Body-centred cubic creestal structur for francium]]

(extrapolatit)
Thermal conductivity15 W/(m·K) (extrapolatit)
Electrical resistivity3 µΩ·m (calculatit)
Magnetic orderinParamagnetic
CAS Nummer7440-73-5
History
Naminefter Fraunce, homeland o the discoverer
Diskivery an first isolationMarguerite Perey (1939)
Main isotopes o francium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
221Fr trace 4.8 min α 217At
222Fr syn 14.2 min β 222Ra
223Fr trace 22.00 min β 223Ra
α 219At
| references | in Wikidata

Francium is a chemical element wi seembol Fr an atomic nummer 87.

References[eedit | eedit soorce]

  1. ISOLDE Collaboration, J. Phys. B 23, 3511 (1990) (PDF online)