Francium

Francium,  ₈₇Fr

General properties
Mass nummer	223 (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) radon ← francium → radium
Atomic nummer (Z)	87
Group	group 1 (alkali metals)
Period	period 7
Element category	alkali metal
Block	s-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 fusion	ca. 2 kJ/mol
Heat o vapourisation	ca. 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)
Electronegativity	Pauling scale: 0.7
Ionisation energies	1st: 393 kJ/mol
Covalent radius	260 pm (extrapolatit)
Van der Waals radius	348 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 conductivity	15 W/(m·K) (extrapolatit)
Electrical resistivity	3 µΩ·m (calculatit)
Magnetic orderin	Paramagnetic
CAS Nummer	7440-73-5
History
Namin	efter Fraunce, homeland o the discoverer
Diskivery an first isolation	Marguerite 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

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