Question

In fluorine group of the periodic table, on going down
(A) Ionic radius increases
(B) Electronegativity increases
(C) Ionisation potential increases
(D) Reactivity increases

Answer 1

Ionic radius is the distance between the valence orbital of the atom and the nucleus which is situated at the centre of the atom. Ionisation potential the potential required to remove one electron from the valence shell of the atom.

Complete step by step solution:
Here, we are being asked about the change in properties like ionic radius, electronegativity, ionization potential and reactivity in the fluorine group upon going down in the periodic table.
-As we go down from the first row in the fluorine group, we get Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At) respectively.
-We know that as we go down in a group in the periodic table, there is an increase in the number of orbits present in the atom. Let’s see how it will affect other properties.
Ionic radius:
-As we go downwards in the periodic table, there is an increase in the number of orbits present in the atom. Hence the radius of their respective ionic form also increases as we go down. So, we can say that the ionic radius always increases as we go downwards in the periodic table.

Electronegativity:
-This property depends upon the ability of the atom to attract the electrons in a bond pair. So, we find that as we go right side in the periodic table, electronegativity increases and as we go down, electronegativity decreases as there is an increase in the volume and thus it cannot attract the electrons in the bond pair as efficiently as smaller sized ions do. Thus, we can say that electronegativity decreases as we go down in the periodic table.

Ionisation potential:
-Ionisation potential shows the energy required to remove one electron from the valence shell of the atom. As we go down in the fluorine group in the periodic table, atomic size increases and hence the valence electron goes far from the nucleus. Thus, it becomes easy to remove its valence electron. Thus, we can conclude that ionization potential decreases as we do down in the periodic table.

Reactivity:
-Reactivity is the ability of the atom to form new compounds upon its reaction with other atoms or molecules. As we go downwards, the atoms’ electronegativity decreases and this makes it less reactive. Thus, we can say that as we go down in the periodic table, the reactivity decreases.

So, correct answer is (A).

Note: Remember that electronegativity depends upon the charge to size ratio of the atom and they should have a tendency to accept electrons. Thus, we can say that electronegativity increases as we go from left side to right side in the periodic table. As we go from up to down in a group, the electronegativity decreases.