Question

Select the group where EN increases down the group.
A) $\text{Ca, Sr, Ba}$
B) $\text{Zn, Cd, Hg}$
C) $\text{F, Cl, Br}$
D) $\text{Li, Na, K}$

Answer 1

Hint:Electronegativity of an element is the tendency of the element to attract the electrons to itself. The elements which are present in different groups in the periodic table have been given in each option. Analyze the given options see their position in the periodic table for increasing order of electronegativity.

Complete answer:
1) First of all we will see which factors of an element affect the electronegativity in the periodic table. When we are going down the group the size of the elements increases this results in a decrease in the electronegativity of an element.
2) Now let's analyze elements in the given options one by one. In option A the elements $\text{Ca, Sr, Ba}$ show the increase in the size when going down the group hence the electronegativity will decrease when going down the group. Hence, this option is an incorrect choice.
3) The option B elements $\text{Zn, Cd, Hg}$ are the transition elements. They show the increase in the electronegativity when going from $\text{Zn}$ to $\text{Hg}$ due to poor shielding of d and f orbital. Hence, this option is the correct choice.
4) The option C the elements $\text{F, Cl, Br}$ show the increase in the size when going down the group hence the electronegativity will decrease when going down the group. Hence, this option is an incorrect choice.
5) In option D the elements $\text{Li, Na, K}$ show the increase in the size when going down the group hence the electronegativity will decrease when going down the group. Hence, this option is an incorrect choice.
6) Therefore, the group $\text{Zn, Cd, Hg}$ shows an increase in electronegativity while going down the group.
Which shows option B as the correct choice.

Note:
As the size of an element increases, its capacity to pull the electrons of other elements decreases making a decrease in the electronegativity. In the periodic table trend, the size of all elements increases down the group, and the electronegativity decreases except for the transition elements where the electronegativity increases down the group.