I've studied electrostatics and we always use Coulomb's law to calculate the force on a particle due to another particle. In an atom there are many electrons and many protons, and if we "take a picture" of an atom, at any given moment, we should see something like this (which is possibly wrong, since matter and waves behaves in the same ways under some conditions. https://en.wikipedia.org/wiki/Matter_wave and because Heisenberg uncertainty principle exists)
Now, we could draw for every single particle the net force acting on that particle. The protons and the neutrons are held together by the strong nuclear force (of which I don't really know anything about..) but what about the electrons? If they all repel each other, and at the same time they are attracted to the nucleus, arrived at a certain position (wherever they may be) they should have a net force acting on them equal to zero and therefore stop. I just know some very basic details of quantum physics, and some electromagnetism and chemistry so I don't know what I'm missing. I'm just thinking about electrons as simple "balls" and in an intuitive way, but could you please tell me what is wrong with my reasoning?