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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


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    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
  4. Jan 12, 2013 #3


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    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)


    Millikan's Nobel presentation (Millikan determined the electron charge)

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