* Cations are formed when an atom loses one or more electrons.

* Electrons carry a negative charge, and they contribute significantly to the atom's size.

* When an atom loses electrons, it loses that negative charge and becomes a positively charged cation.

* With fewer electrons, the electrostatic attraction between the nucleus and the remaining electrons increases. This causes the electron cloud to shrink, resulting in a smaller ionic radius.

In summary:

* Parent atom: More electrons, larger size.

* Cation: Fewer electrons, smaller size.