can someone give me an intuitive picture of why electrons don't collide with protons?

I know that electrons move in a sort of cloud, which is our 'orbital', and that they mainly behave like electromagnetic wave because of their very tiny mass. However, how comes they don't collide with the protons? I seriously didn't find a good explanation of these neither by professors I talked to nor by books, so a thousand points from me if you are able to get me into this.

Keep in mind that I am not looking for values, equations, or quantitative explanation of this, for that I have read enough, but for a picture. Think about the subatomic particles as you see them in your mind and describe their relationship.

  • $\begingroup$ @bon Thank you sir, I appreciate such a nice welcoming! $\endgroup$ Commented May 22, 2016 at 18:13
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    $\begingroup$ They kinda do collide, only they don't seem to care much. $\endgroup$ Commented May 22, 2016 at 18:24
  • $\begingroup$ @Ivan Neretin Ok so far it matches my picture, since the probabilistic cloud of the lowest principal quantum number would cover the area of the nucleus as well, but since I am used to think about the acid and base behavior within molecules, I can't understand what is the barrier between electrons and protons.. $\endgroup$ Commented May 22, 2016 at 18:35
  • $\begingroup$ chemistry.stackexchange.com/questions/15727/… $\endgroup$
    – Mithoron
    Commented May 22, 2016 at 18:46
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    $\begingroup$ "Collide" is the wrong word: it implies some kind of bouncing solid spheres, which are just not there. There is nothing to collide with. An electron does not just sometimes behave like a wave - it is a wave. Imagine a sea wave running against a lone rock. It will just run around the rock and continue on its way. Sure, once in a great while a wave would bring the rock down. Well, an electron has the chance to react with proton by means of K-capture. $\endgroup$ Commented May 22, 2016 at 19:18

1 Answer 1


They do collide. But it's not like cars crashing and smashing each other up on the highway. Their quantum mechanical wavefunctions overlap and the electrons do in face settle in with wavefunctions that are centered on the nucleus. But the low mass of the electrons, the Heisenberg uncertainty principle (which has its greatest effect on low-mass particles), and the Pauli exclusion principle (electrons can't all pile up in the most stable quantum state) cause the electron wavefunctions to get diffused out around the nucleus. Instead of getting smashed up, the electrons basically surround snd embed the atomic nucleus.

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    $\begingroup$ This is a good answer. Pretty similar to the one by @Ivan Neretin in the comments, even though his answer was even more accurate onto giving an example. Thank you both guys! $\endgroup$ Commented May 22, 2016 at 19:56
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    $\begingroup$ My comment is not more accurate (which, BTW, is why I'd rather not turn it into an answer). If anything, it is more picturesque, but remember: the whole thing about sea waves and rocks is but a metaphor, and those are not intended to draw practical conclusions. $\endgroup$ Commented May 22, 2016 at 20:18
  • $\begingroup$ You are welcome. I woll make sure to +1 Ivan's comment. $\endgroup$ Commented May 22, 2016 at 20:28
  • $\begingroup$ @Ivan Neretin yes of course I know that, but it's a good metaphore which gives the idea of that. $\endgroup$ Commented May 23, 2016 at 9:10

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