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In this question the OP asked, if electron and proton ,which are very near to each other,are left to attract in a straight line then what will happen? The answer was that a Hydrogen atom will form. But I have a doubt. Hydrogen atom has an angular momentum. When the particles electron and protons attracted each other, there was no angular momentum but hydrogen atom, which formed due to attraction,has angular momentum therefore it violates the conservation of angular momentum.

So my question is - Why would a hydrogen atom form if electron and proton ,which are very near to each other,are left to attract in a straight line, given that it violates conservation of angular momentum? Also kindly note that no torque is applied to create circular motion. Wouldn’t some kind of force would be required to create a angular motion from a linear motion?

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    $\begingroup$ Hydrogen atom has an angular momentum. If you have only learned the Bohr model of hydrogen, you might think this. If you have heard of $s$ states (or $\ell=0$ states) in the Schrödinger model, you should not think this. $\endgroup$
    – Ghoster
    Nov 3, 2023 at 5:03
  • $\begingroup$ "Why would a hydrogen atom form if..." Who says that it necessarily would? Some "answer" you linked to that was actually answering a different question? The linked question asks about an electron and proton very close to each other. You did not specify anything other than "left to attract each other." If the electron and proton are the only things in the universe and are coming at each other from miles away, they will not form a hydrogen atom. $\endgroup$
    – hft
    Nov 3, 2023 at 5:29
  • $\begingroup$ Firstly, particles have intrinsic angular momentum known as spin. That is not the problem necessarily to atomic formation. Secondly, I recommend reading up on Photorecombination. $\endgroup$
    – RC_23
    Nov 3, 2023 at 5:33
  • $\begingroup$ Related question: Does angular momentum of electrons imply motion around the nucleus? $\endgroup$
    – khaxan
    Nov 3, 2023 at 5:34

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You raise a good question because formation of a hydrogen atom is not as simple as it might appear at first sight. The question What happens when we bring an electron and a proton together? goes into a lot of the details.

However angular momentum is not usually a problem. The ground state of the hydrogen atom has a zero angular momentum so if the electron and proton are headed towards each other with zero angular momentum this won't prevent formation of the atom. If they do have some angular momentum this isn't a problem either as the atom can form in an excited state then emit photons to carry away the excess angular momentum.

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