When a chlorine atom forms an ion, it gains electrons, making it negative. A neutral chlorine will become a chlorine with a -1 charge. When it gains an electron, the radius increases.
When a sodium atom forms an ion, it loses electrons, making it positive. A neutral sodium will become a sodium with a +1 charge. When it loses an electron, the radius decreases.
a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.
