Why don't electron stick to proton?

Question

Why don't electrons stick to protons if there’s electrons whizzing around the outside of an atom and the protons are the positive bit in the middle? Why don't the two just collapse in on each other?

Answer

Naked Scientist Dave Ansell got stuck into this question...

Okay, in a very simple sense, they do stick to protons as much as they can.

They're attracted to protons and so they form atoms. An atom is essentially electrons stuck to protons.

What you really are asking though is why don't they get any closer than they do?

It's all basically to do with the fact that electrons - in fact, everything - has wave properties. And the electron's wavelengths are about a similar sort of size as an atom, and that's the reason why atoms are that sort of size over the order of the wavelength in electron.

And so you can't really compress a wave any smaller than one or few wavelengths. So the electron can't get any smaller than that without actually changing its properties entirely. Which means it can't actually get any closer to the proton in the centre of the nucleus than it does. So it's stuck as close as it can.

You can cause - if at very high pressures - electrons essentially to react with protons and turn into neutrons, and this is what happens in neutron stars. A neutron actually isn't stable just lying around in the atmosphere, or in a vacuum. It decays in about 14 minutes into an electron and proton and forms into a hydrogen atom.