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What physical experiment would tell you how many electrons an atom has

  1. Jan 11, 2013 #1
    How did scientists/chemists experimentally determine how many electrons an atom has?
    Hydrogen, carbon, oxygen, etc....
    I'm wandering what physical experiment would tell you how many electrons an atom has?
     
  2. jcsd
  3. Jan 12, 2013 #2

    DrDu

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    Science Advisor

    Re: Electrons

    They determined the nuclear charge from the wavelength of the K_alpha lines in X-ray spectra and relied on the number of electrons being equal due to charge neutrality. See
    http://en.wikipedia.org/wiki/Moseley's_law
     
  4. Jan 12, 2013 #3

    Astronuc

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    Staff: Mentor

    Re: Electrons

    During the 1890s and early 1900s, there were a number of scientists working on atomic structure: Rutherford, Bohr, Thomson, and many physicists, and numerous chemists.

    Rutherford had made an estimates of the nuclear charge in conjunction the work of others.

    J. J. Thomson's Nobel lecture (Thomson determined the electron's e/m)
    http://www.nobelprize.org/nobel_prizes/physics/laureates/1906/thomson-lecture.pdf

    http://en.wikipedia.org/wiki/Robert_Millikan

    Millikan's Nobel presentation (Millikan determined the electron charge)
    http://www.nobelprize.org/nobel_prizes/physics/laureates/1923/press.html

    http://www.wou.edu/las/physci/ch412/perhist.htm
     
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