Question

Which of the following correctly compares the radii of Cl and Cl−?

Answer 1

Answer:

Cl has a smaller radius than Cl− because Cl− has an expanded electron cloud.

Explanation:

Definition of atomic radii:

The atomic radius is the distance between center of two bonded atoms.

Trend along period:

As we move from left to right across the periodic table the number of valance electrons in an atom increase.The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases.

Trend along group:

In group by addition of electron atomic radii increase from top to bottom due to increase in atomic number and addition of extra shell.

In this way Cl⁻ will have the largest atomic radii because one extra electron is added and electronic cloud more expanded as compared to neutral atom.