Alpha radiation would seem to occur when a pair of protons and neutrons are magically plucked from the amorphous (i.e. having no particular structure) nucleus of a heavier atom.
Some of the problems associated with this approach, but which are conveniently ignored, include:
- What happens to the electron pair associated with the removed protons?; Is an anion created?
- how can a positively charged alpha particle manage to pass through heavily populated electron orbitals without disturbing or interacting with them?;
- Why do only four nucleons separate from the nucleus – is this some
type of magic number? Why not 1 nucleon (a hydrogen atom or a
neutron), 2 nucleons (e.g. deuterium), or 3 (e.g. helium-3) etc. ?
Because of the problems with orbital electrons, it is quite difficult to find a diagram that shows exactly how the alpha radiation process takes place. Most diagrams simply ignore the existence of the orbital electrons; a few show them, but only in an over-simplistic and unconvincing way (see lower figure below).
Best Answer
It's definitely not the case that the electron cloud is undisturbed. The process is quite violent on the scale of the atom undergoing alpha emission.
The electron cloud is excited by the process of the emission of the alpha particle, so the remaining ion isn't in its ground state. Moreover, the remaining nucleus also gets some recoil from the alpha particle, which also adds to disturbance of the electron cloud. The disturbance may in fact lead to some electrons being ejected from the ion.
For example, here is a 1975 paper which reports the "shake-off" of electrons from polonium-210 nuclei during the alpha decay to lead-206. The experiment observed simultaneous alpha particles, emitted electrons, and x-rays from the filling of the "hole" in the lead's electron cloud. Current best results suggest about ten or fifteen electrons are ejected per million polonium alpha decays.
Why it's usually "conveniently ignored" is because chemistry is rarely of interest when discussing nuclear physics.