Why doesn’t an electron in a hydrogen atom fall onto the nucleus?
If the position of an electron near the nucleus changes within the distance Δr = r, then according to the uncertainty relation its momentum has an uncertainty Δр = h / Δr. The connection between the kinetic energy E and the momentum p of the electron in the atom leads to the fact that with a decrease in the size of the region around the nucleus in which the electron is located, its kinetic energy increases in inverse proportion to the square of the distance, i.e. faster than the potential energy of an electron in the Coulomb field of the nucleus decreases. When an electron and a nucleus approach each other, an increase in its kinetic energy, starting from a certain distance, exceeds the decrease in potential energy, and the total energy does not decrease, but increases.