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It is known that the electrons aren't really at any one place at any time at all. Instead they exist as a sort of cloud and "circulate" around the nucleus in their orbitals. The high-school textbooks say that "the electrons don't strictly follow a set path around the nucleus. Electrons move in every direction, but they are limited to their own area". Assume I am an electron and my house is a nucleus, and I could fly around my house in an similar way the electrons do... I would then try to avoid the chimney-part of my house for example.
What I wonder is:

  1. Will the electron certainly occupy all the physical points of its own cloud/orbital, given long enough time,

or

  1. is the electron moving absolutely chotically in its orbital without any specific trajectory - might even stay and vibrate at the same "place" for some time, and might there be "places"/points in the orbital that the electron would never happen to "visit" in its motion around the nucleus?

I hope the questions are understandable!

Adelina Mitkova
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2 Answers2

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The answer is that we don't know. The physical theory of electrons in atoms can be loosely summarised by saying that certain properties of an electron in an atom can be modelled by particular equations, the solutions of which represent the relative probabilities of an electron being in particular parts of the space around the centre of the atom. Experiments suggest that the electron is a point-like particle whose volume is very small compared to an atom, so naively one might expect that the electron whizzes around the volume of space occupied by the atom, but it is possible that the behaviour of matter at such tiny scales is quite different to our common sense conceptions.

Your conjecture about the possibility of an electron lurking in particular spots while never visiting others doesn't quite fit with the probabilistic interpretation conventionally associated with the electron wave function, which implies that an electron could be found anywhere. The wave functions don't have a sharp cut-off, but tend to zero over distance, so in theory there is a very very very very etc small probability of an electron being found a long way from its atom.

Since quantum theory doesn't say much else about where the electron 'really' is, and we haven't yet got a better theory that does, you will find that different people have various preferred 'interpretations' of quantum theory which try to have a more satisfying picture of what actually goes on. Some of the interpretations are less popular than others. For example, some people assume that the electron might actually be smeared out over the whole volume of the orbital and yet somehow condense to a point when it interacts with devices designed to detect it. The difficulty lies in telling the difference between bona fide interpretations (ie those that are entirely consistent with all the prediction of the theory and all the experimental data) and the rest.

Marco Ocram
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  • Thanks for replying! You say "For example, some people assume that the electron might actually be smeared out over the whole volume of the orbital and yet somehow condense to a point when it interacts with devices designed to detect it." Which are those people? Are there any experiments/articles covering the topic or is that just speculations and someone´s own theories? – Adelina Mitkova Jan 25 '22 at 23:09
  • It is all speculation. If there were any meaningful experimental data, then there would be no room for speculation. – Marco Ocram Jan 26 '22 at 08:08
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The cloud (or orbital ) , that you are talking of , is actually the space vector for which the ψ ( of Schrodinger's equation ) has some solutions .The electron wave is shown as somewhat like the dispered wave over that space . However , when we actually do find the position for some instants , the space vector and wavefunction collapses . Now , as opposite to above , where ψ is orthogonal , that space , plane or point are called nodes . How does electron traverse between orbitals through nodes , how does it traverse inside the cloud ? Are all ongoing topics going on in the quantum mechanics .

Abbas
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  • Seems to me that the movement of an electron in its orbital is in it self the proof of what I mean above - that the electron avoids some parts of the space around the nucleus and prefers others. Could that not be true? – Adelina Mitkova Jan 28 '22 at 21:34
  • It isn't that way as you are thinking . I guess your book was introducing wave mechanical idea and criticizing Bohr's idea of special orbits . Indeed it is true that electrons movement is not so free and it is prohibited to enter some spaces . For example , an electron is again prohibited to move between these quantum states , n = 1 to n= 2 , through space . It's not allowed for them to move through so . But , we know that it happens and that's what results in the huge branch of spectroscopy , etc . – Abbas Jan 29 '22 at 03:54
  • The main idea is that to try avoiding the behavious of electron by just thinking as in normal life . You must have a mathematical view instead of just "eye" type view . – Abbas Jan 29 '22 at 03:55