How do radiation particles escape the atom unaffected in radiation?

Question

Alpha radiation is the emission of two protons and two neutrons from the nucleus of an atom (helium nucleus). Beta radiation is the emission of a high-speed electron from the nucleus of an atom as a result of a neutron decaying into a proton and an electron.

In both scenarios, an overall charged particle or group of particles is being ejected from the nucleus in a random direction. Radioactive decay and events of radiation being emitted like this are more common among atoms at the bottom of the periodic table (higher atomic number/number of protons), which makes sense in the sense that there are more protons and neutrons existing in the atom for this to take place, so the probability is higher (radioactive decay and radiation is random).

If we draw a straight line from the nucleus where the alpha/beta particles are going to leave the nucleus, the probability that there is an electron in that path increases as atomic number increases (in atoms, protons and electrons increase with direct proportion) (correct me if I'm wrong). Why does this never happen? How do the electrons orbiting the nucleus 'dodge' the alpha/beta particles emitting from the nucleus? 1. Does the repelling force between electrons act even quicker than the speed at which the beta particles are emitted? Or 2. are the electrons orbiting the nucleus so small that the chance of the radiation particles coming into contact with the orbital electrons is extremely small?

In the first case, the question still holds for beta particles, how does the beta particle (just one electron) escape the atom and resist the nuclear attraction as it is emitted from the nucleus? Is the 'pushing' force from the nucleus greater than the 'pulling' attraction force, leading to a resultant force away from the nucleus, causing the particle to accelerate away from the nucleus? Why doesn't the atom gain its own electron and stay an atom, becoming the next element along the periodic table?

In the second case, which I would say is more likely, the question still holds for alpha particles. The strength of the forces of attraction/repulsion are the same. So theoretically the "helium nuclei" that are alpha particles would attract electrons off of the atom as it got emitted since the electrons are more exposed to that nucleus being emitted than the original nucleus that the alpha particle came from. In this case the original atom would lose two electrons and be ionised, and the alpha particles would become a helium atom once far enough away from the original atom. But this isn't observed.

Or is there a third case? I need some serious clarification on particle physics since I'm now doing Physics in college (A-levels). In high school we were just told "the alpha/beta particle just leaves the atom" and when I asked why they said "I don't know". Also, I hope this was concise, my previous post were deleted due to lack of focus.

Answer 1

In answer to your question about beta particles, they don't stick around and become part of the atom because they have way too much kinetic energy.

The least energetic beta decay occurs in H-3 where beta particles have a maximum energy of 0.018 MeV and an average energy of about a third of that, 0.006 MeV or 6000 electron volts.

If we look at first ionization energies for atoms we see that they max out at about 25 electron volts so the electrons produced by beta decay have hundreds of times (at least) more energy than they need to escape the atom.

This would produce a positive ion rather than a neutral atom because the nucleus now has one more positive charge.

Answer 2

Let me clear up a number of misconceptions in this question:

Radioactive decay ... [is] more common among atoms at the bottom of the periodic table, which makes sense in that the probability is higher.

This is misleading. Don't think of each nucleon carrying some constant decay probability, and the more nucleons, the higher the probability for decay, that's not what's happening. Decay probabilities mostly depend on the energy difference between initial and final state (read up on the nuclear shell model) and the conservation laws.

If we draw a straight line from the nucleus where the alpha/beta particles are going to leave the nucleus, the probability that there is an electron in that path increases as atomic number increases

Again misleading as you shouldn't think of particles and lines but of wave packets. That said, it doesn't lead you to wrong conclusions here.

Why does this never happen?

It almost always happens. The daughter atoms from an alpha decay are typically positively charged.

are the electrons orbiting the nucleus so small that the chance of the radiation particles coming into contact with the orbital electrons is extremely small?

The opposite is true, their wave packets are smeared across the entire atom.

how does the beta particle (just one electron) escape the atom and resist the nuclear attraction as it is emitted from the nucleus?

Typical atomic binding energies are of order of a few electronvolts. Typical nuclear decay energies are Mega-electronvolts. Thus, the binding energy is typically negligible.

Why doesn't the atom gain its own electron and stay an atom, becoming the next element along the periodic table?

In nuclear decay, one atom does transform into another one in the periodic table.

But this isn't observed.

Says who.