Question

Rank the elements in each of the following sets in order of increasing IE₁:
(a) Sb, Sn, I
(b) Sr, Ca, Ba

Answer 1

Explanation:

Ionization energy is defined as the energy required to remove the most loosely bound electron from a neutral gaseous atom.

When we move across a period from left to right then there occurs a decrease in atomic size of the atoms. Therefore, ionization energy increases along a period.

But when we move from top to bottom in a group then there occurs an increase in size of the atoms. Hence, ionization energy decreases along a group.

(a)  As Sb, Sn and I are all period 5 elements. Hence, these elements are arranged in order of increasing $IE_{1}$ as follows.

                             Sn < Sb < I

(b)  As Sr, Ca, and Ba are all elements of group 2a. Hence, these elements are arranged in order of increasing $IE_{1}$ as follows.

                            Ba < Sr < Ca