Now certain of the nucleons [those that are radioactive] exhibit within the nuclei a halo orbiting around a stable core. As a result, they take up a great deal more space than ones do that [being non-radioactive] have the same mass.

But nuclei with a high binding energy (or strong force) overwhelm the repulsive electrical force [which drives like charged protons apart], where as light nuclei do not.

With the radioactive nuclei, however (having too many or too few nuetrons), the state of nuclear forces tip; As a result, the nucleons scramble to find stability.

In some cases, however, research has shown stability is found only when the extra nucleons part from the core and begin to orbit, forming a halo.

An experiment was conducted in which aluminum and copper targets were bombarded by a beam of lithium11 nuclei and its impact measured. It was determined that its radius was pegged at 3.16 femtometers (or equal in size to a nucleus with three times as many nucleons).

Such experimentation suggests that proton halos may exist as well, but further research into the phenomenon will be required to verify this assessment.