Question

What occurs when an atom of chlorine forms a chloride ion?

A. The chlorine atom gains an electron, and its radius becomes smaller.
B. The chlorine atom gains an electron, and its radius becomes larger.
C. The chlorine atom loses an electron, and its radius becomes smaller.
D. The chlorine atom loses an electron, and its radius becomes larger.

Answer 1

The answer is B. The chlorine has 7 electrons at the outer shell. So it will gain one electron to become stable when forms a chloride ion. And the gained electron will stay at the outer shell. So the radius becomes larger.