[no username inserted]

Can somebody explain what the exact reason for the fact that electron and proton do not attract each other in an atom is ?
Is the velocity of electron equal in different atoms? For example the electron in Hydrogen and the electrons in Helium?

[Corribus]

You are thinking too much like classical physics.

Here is a good explanation:

http://chemwiki.ucdavis.edu/Physical_Chemistry/Quantum_Mechanics/Atomic_Theory/Why_atoms_do_not_Collapse