What would have happened if electron fell into the nucleus of an atom
The intrinsic property of the electron is to be in motion—the electron has the intrinsic linear momentum. Now we have the electron in an atom. The electron does not move in one direction only because the Coulomb force acting from the right angle changes its direction, and so the electron revolves around a nucleus.
At this situation, the electron cannot fall into a nucleus since the Coulomb force is constant there, and so this force keeps the constant radius of an orbit. Yet, the direction of the linear momentum does not point to a nucleus. So is according to nature.
Nature does not allow to have the reaction: the electron + proton = neutron. The natural process runs in the reverse direction—the neutron decays to the electron and the proton (+ neutrino and photons). So is the one-way process, since an entropy cannot be returned.
Certainly, strange conditions exist in the universe that may overcome this natural process. We have stars, let’s have the sun. There run nuclear reactions like a proton plus a proton and so on. What brings then together is gravitation, and so the extreme pressure on atoms of hydrogen. Mathematical logic due to the Coulomb Law says that the electrons are pushed in protons to form neutrons there. However, it is not so. The atoms are stripped and form a plasma of protons and a ‘cloud’ of electrons. The additional pressure on the plasma causes the nuclear fusion.
If electrons would have pushed in protons, then a plasma of neutrons was in the core of the sun and the neutrons were entering that fusion. Hence, the electron does not react with a proton.
The more extreme conditions are in the core of bigger stars than Sun, and so when they died, they still are not atoms but just nuclei. However due to their density is said, they are neutron stars, so is supposed they are neutrons in ‘plasmatic’ state. Thus, we may accept the electron falls in a nucleus and created a neutron just at the neutron stars. However, the speeds on surfaces of neutrons stars are near to the intrinsic speed of the electron, and so this should be taken also in consideration why the atomic matter is not there.
Anyway the conclusion is, we should not await the fall of the electron in a nucleus in accordance with nature. If it would happen abnormally, then it decays immediately back to the proton and the electron, not just because the spontaneous decay of the neutron, but because we do not have any neutrino there. Hence, the mathematical approach—the applying of the Coulomb Law for bringing the electron to the proton and then to bind them—does not work in physics (nature). Namely, the Coulomb Law is valid for charged macro objects, and so should also be valid for the quantum level where are particles carrying the quanta of electricity. But the ‘evolution’ process— when new (subatomic) particles evolve as the proton and the neutron from the neutron—is complex process, which the Coulomb Law initiates and then other physical laws are applied there.
In a case of beta rays to hit a nucleus, the electron interacts with a nucleus through inelastic or elastic collision. The most liked interactions are elastic collisions, when the electron is interacting with few subatomic particles until becomes a satellite of a nucleus. Thus, such an atom becomes an ion (anion).