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Does an electron in p orbital move around nucleus or move randomly in any individual lobe of p orbital. if it were to move around nucleus then does p orbital move along with it?

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    $\begingroup$ Electrons are not particles. They are described by the wavefunction-the probability amplitude to find an electron in a coordinate. It is not moving in the lobe. The lobes are functions of purely mathematical construct; one lobe is positive while the other is negative. How it is moving we don't know due to the Uncertainty Principle. $\endgroup$ – user36790 Oct 31 '15 at 10:33
  • $\begingroup$ I'm not sure how many physicists think of eigenfunctions of an atom in a dynamic sense (that you've mentioned). I guess (and maybe wrong) that for most eigenfunction distribution is the electron, thus static and don't move. You can change basis from spatial to mixed representation (although it would be very unpleasant) of slices (x,y,pz) and get the momentum perpendicular to (x,y) plane for z of your choice. (similar for any plane ax+by+cz+d=0) $\endgroup$ – Alexander Oct 31 '15 at 11:31
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    $\begingroup$ If you think of an electron as a little marble that revolves around the nucleus, you'll start running into contradictions right away. It's not a good model. $\endgroup$ – garyp Oct 31 '15 at 13:33
  • $\begingroup$ The more I keep looking at your statements, the more it seems to me that chemists are partially at fault for the trouble students have with understanding quantum mechanics. In beginner's level chemistry it is customary to treat electrons as objects that are assigned to orbitals. This, of course, is not the case, it's just a way of counting total charge in atoms in a way that is consistent with chemical reactions, which, at the end of the day, are considered classical (even though they are not). $\endgroup$ – CuriousOne Oct 31 '15 at 21:43
  • $\begingroup$ @CuriousOne: That's the main problem of the chemistry textbooks prevalent in India; they transit from doing some outdated Dalton's law & some stoichiometry abruptly to atoms introducing orbitals without preparing any base for Quantum mechanics. Many like OP succumb to that horrible transition & start daydreaming of electrons as some balls moving in those specific paths called orbitals. This is completely nonsense! $\endgroup$ – user36790 Nov 2 '15 at 13:49
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The lobes are regions where you have a non-zero probability of finding an electron. These regions have varying shapes for different types of orbitals. It wouldn't make sense to think that orbitals are actually paths of some sort, where electrons whizz around. You'll know this is wrong if you try to understand the uncertainty principle.

The uncertainty principle prevents us from simultaneously measuring the momentum and position of an electron, up to sufficient accuracy.

Also, read: What is the uncertainty principle?

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  • $\begingroup$ then can we never how electron moves around nucleus. $\endgroup$ – Anubhav Goel Oct 31 '15 at 11:21
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    $\begingroup$ No, that is why they are associated with wavefunctions @Anubhav Goel. $\endgroup$ – user36790 Oct 31 '15 at 11:23
  • $\begingroup$ Actually the orbitals are like a contour map, its just where the probability density transitions from one value to another where the value is chosen to make the picture look nice. The probability density is nonzero almost everywhere. You need an infinite potential to confine a wave statically. You probably actually know this, so the stories and myths about orbitals are getting so bad its affecting you too. $\endgroup$ – Timaeus Nov 1 '15 at 5:01
  • $\begingroup$ Yes, they probably are. I'll edit the answer. $\endgroup$ – Hritik Narayan Nov 1 '15 at 12:55
  • $\begingroup$ I thought deletion would work but apparently the OP hasn't unaccepted this answer yet $\endgroup$ – Hritik Narayan Nov 1 '15 at 12:55
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As usual, you can re-express the wave-function in momentum space (it's just a Fourier transform away from the spacial wave-function for bound state which is really nice). But that does not tell you how the electron moves anymore than the spacial wave function tells you where it is. Instead, it tells you the probability distribution function for results of measuring the electron's momentum just as the position wave-function gives you the PDF for position measurements.

I'm not an expert in those measurements, but I've found a reference in which the momentum-state of electrons in xenon atoms was measured so sufficient precision to show clear relativistic effects (PDF link) (J.P.D.Cook, J.Mitroy, and E.Weigold, PRL. vol 52. no 13. p1116 1984).

The equivalent measurement for protons in a nucleus is done reasonably often---indeed my dissertation work included extracting the momentum-space PDF's for protons in a few nuclei.

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In addition to these two excellent answers I'd like to point out that the deceptively smooth surfaces of orbital graphical representations found in text books and web pages, like this excellent rendition of a 2p orbital, below are surfaces where the electron probability density is the same. In no way do they represent paths or 'orbits'.

enter image description here

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