Rubidium is a chemical element wi seembol Rb an atomic nummer 37. Rubidium is a saft, sillery-white metallic element o the alkali metal group, wi an atomic mass o 85.4678. Elemental rubidium is heichly reactive, wi properties seemilar tae those o ither alkali metals, sic as very rapid oxidation in air. Naitural rubidium is a mix o twa isotopes: 85Rb, the anly stable ane, constitutes 72% o it. The remainin 28% is the slichtly radioactive 87Rb wi a hauf-life o 49 billion year—mair nor three times langer than the estimatit age o the universe.

Rubidium, 37Rb
Template:Infobox element/symbol-to-top-image/alt
Rubidium
Pronunciation/rˈbɪdiəm/ (roo-BID-ee-əm)
Appearancegrey white
Standard atomic weight Ar, std(Rb)85.4678(3)[1]
Rubidium 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
K

Rb

Cs
kryptonrubidiumstrontium
Atomic nummer (Z)37
Groupgroup 1 (alkali metals)
Periodperiod 5
Blocks-block
Element category  Alkali metal
Electron confeeguration[Kr] 5s1
Electrons per shell2, 8, 18, 8, 1
Pheesical properties
Phase at STPsolit
Meltin pynt312.45 K ​(39.30 °C, ​102.74 °F)
Bylin pynt961 K ​(688 °C, ​1270 °F)
Density (near r.t.)1.532 g/cm3
when liquid (at m.p.)1.46 g/cm3
Treeple pynt312.41 K, ​? kPa[2]
Creetical pynt2093 K, 16 MPa (extrapolatit)[2]
Heat o fusion2.19 kJ/mol
Heat o vapourisation69 kJ/mol
Molar heat capacity31.060 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 434 486 552 641 769 958
Atomic properties
Oxidation states−1, +1 strangly basic
ElectronegativityPauling scale: 0.82
Ionisation energies
  • 1st: 403 kJ/mol
  • 2nd: 2632.1 kJ/mol
  • 3rd: 3859.4 kJ/mol
Atomic radiusempirical: 248 pm
Covalent radius220±9 pm
Van der Waals radius303 pm
Colour lines in a spectral range
Colour lines in a spectral range
Spectral lines o rubidium
Ither properties
Naitural occurrenceprimordial
Creestal structurbody-centred cubic (bcc)
Body-centered cubic creestal structur for rubidium
Speed o soond thin rod1300 m/s (at 20 °C)
Thermal expansion90 µm/(m·K)[3] (at r.t.)
Thermal conductivity58.2 W/(m·K)
Electrical resistivity128 nΩ·m (at 20 °C)
Magnetic orderinparamagnetic[4]
Young's modulus2.4 GPa
Bulk modulus2.5 GPa
Mohs haurdness0.3
Brinell haurdness0.216 MPa
CAS Nummer7440-17-7
History
DiskiveryRobert Bunsen an Gustav Kirchhoff (1861)
First isolationGeorge de Hevesy
Main isotopes o rubidium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
83Rb syn 86.2 d ε 83Kr
γ
84Rb syn 32.9 d ε 84Kr
β+ 84Kr
γ
β 84Sr
85Rb 72.17% stable
86Rb syn 18.65 d β 86Sr
γ
87Rb 27.83% 4.9×1010 y β 87Sr
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References

eedit
  1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  2. a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nt ed.). CRC Press. p. 4.122. ISBN 1439855110.
  3. http://www.owlnet.rice.edu/~msci301/ThermalExpansion.pdf
  4. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  5. Standard Atomic Weights 2013. Commission on Isotopic Abundances and Atomic Weights