Question

Which of the following properties increases on going down from F to I in group- VII-A of the periodic table?
A. Electronegativity
B. Volatile Nature
C. Ionic radius
D. Oxidising Power

Answer 1

Hint: Group VII consists of fluorine, chlorine, bromine, iodine and a radioactive element astatine. To answer this question, first we must know about the properties. Let us discuss the properties to answer this question.

Complete Step by Step Solution:
We know group 17 are referred as halogens and are known as halogen groups. This group consists of fluorine, chlorine, bromine, iodine and a radioactive element astatine.

Let us discuss the properties of the halogen family:
Electronegativity: It is the tendency of an atom to attract the pair of electrons towards itself. As we go down the group, size of the atom goes on increasing and hence electronegativity goes on decreasing
So the order of electronegativity in halogens is F > Cl > Br > I

Volatile nature: Volatile nature of the molecule means its ability to quickly convert into the gas at room temperature. As we move down the group, size goes on increasing due to increase in the Van Der Waal forces and hence the boiling point increases and volatile nature goes on decreasing.
So the order of volatile nature in halogens is F > Cl > Br > I

Ionic radius: It is simply the size of an atom. We know as we move down the group, the number of protons and neutrons increases and thus the atomic radius goes on increasing.
So the order of atomic radius in halogens is I > Br > Cl > F

Oxidising power: Oxidising power is the ability of the atom to gain the electrons. Fluorine is a powerful oxidising agent. It is due to high electronegativity and small atomic radius. As we move down the group, oxidising power goes on decreasing.
So the order of oxidising power is F > Cl > Br > I

Hence we see that only ionic radius increases on going down from F to I in group- VII-A of the periodic table.
Thus, Option (C) is correct.

Note: In this type of questions, students must have a deep knowledge of the properties of halogens and the reason behind them being able to give the correct answer. There is a minor difference between all the properties of halogens.