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Wave properties of an electron

  1. Jul 28, 2012 #1
    I have read for the last 2 years that an electron is a particle that revolves around a nucleus. That has made me believe that an electron has only particle nature however my assumption that an electron has only particle nature has proved false. I want to know what somebody means when he says an electron is a wave. Electron is a particle, how can it have wave properties. Does it imply that an electron moves 1000-100000 times around the nucleus when we say it's frequency is 1000-10000 or what so ever. Thanks in advance for help...
  2. jcsd
  3. Jul 28, 2012 #2


    Staff: Mentor

    An electron is neither wave or classical particle - it is a quantum object - often called a quantum particle or, shortened to just particle - but it must always be understood to be a quantum particle - not a classical particle. It sometimes behaves like a particle in the sense it has a definite position you can measure in some experiments and sometime like a wave in the sense solutions in certain problems is wavelike - but in reality is neither.

    The election doesn't move around the nucleus at all because that is a classical particle like picture and it isn't that. What it does around a nucleus is unclear but you can predict probabilities of where it would be if you could measure its position.

    The very essence of QM is the superposition principle which says if a quantum object can be in state 1 or state 2 then it can also be in a state that is in some sense partly in both states. Inside an atom it is in a weird superposition of positions - partly in many different positions at the same time. Don't even try to imagine it - you can't. That is the sense it can be wavelike. The equations that specify how much it is partly in these different positions is wavelike - but is not really a wave in anything.

    Last edited: Jul 28, 2012
  4. Jul 28, 2012 #3
    Hey Kiddy!

    You can read about de Broglie wavelength in wikipedia. And the double slit experiment..also called Young's experiment..both are in Wikipedia and explain how a 'particle' is also a wave. A 'particle' is a quanta [a local lump] of a wave..a local concentration of an extended wave.

    It is more modern to view an electron as a wavelike entity sort of like a 'cloud' around a nucleus..
    What does this look like?
    good illustrations here:

    An electron in the presence of a nucleus is constrained.....to certain energy levels, for example...now called orbitals [not planet like orbits of the old classic deswcription].

    Think of a violin string as an analogy: the ends are constrained,fastened, so it can have only certain tones...certain vibrational patterns and associated energies. It's energy levels are constained to certain values...it's degrees of freedom are limited. like a bound electron.

    Think of the electron as a wave: When it's in free space the wave is everywhere, it extends all over the place. But when attracted by protons in a nucleus, for example, that wave is now localized...it's constrained and so its different from the free space case. And the constraint is also modified by the presence of other electrons and additional protons. Since the energy is contained in the wave, changing it's configuration via the presence of nearby particles changes the wave characteristic and most likely energy levels where the electron will be found. It's very unlikely for the electron to be found between allowed energy levels...that is unlikely to be found between designated orbital energy levels.

    In contrast, a free electron can take on any energy level. But when it is part of an atom or a larger structure, it's constrained...it's degrees of freedom are determined and limited by the whole structure. So an electron's energy levels and degrees of freedom are determined by the numbers of protons in the nucleus as as well as the particular structure of a lattice, as examples. The Schrodinger wave equation describes these.

    Another way to say this: This SIZE of an electron is determined by it's environment...in fact in some lattice configurations its observed momentum and mass also seems to change!!! Such fundamental particles may be 'elemenatry' but they are not simple!!!!
  5. Jul 28, 2012 #4


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    Gold Member

    Seems like a wave if probed at a scale much smaller than the wavelength, and it will seem like a particle is probed at a scale much bigger than the wavelength.

    This guy seems to make everything seem simple:
    Last edited by a moderator: Sep 25, 2014
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