Chapter 8, Problem 8.52QP

Interpretation Introduction

Interpretation:

The given set of atoms has to be arranged in increasing order of ionization energy.

Concept Introduction:

• An atom can be converted into an ion by removing an electron from its outermost shell or adding electron to the outermost shell.  An amount of energy is required to removed an electron from the outermost shell of an atom to form a cation.  The minimum energy required for removing an electron from an atom in gaseous phase is known as ionization energy. 
• If one electron is removed from the atom to form a cation, the energy required is known as first ionization energy.  If another electron is removed from the formed ion, the energy required is known as second ionization energy and this goes on.  Second ionization energy is higher than the first ionization energy because the effective nuclear charge increases.
• The trend followed in a periodic table for ionization energy is, it increases across the period and decreases down the group.  This is because; across the period, the electrons are added to the same orbital and hence decrease in shielding.  However, down the group, the electrons are added to a new subshell and hence increase in shielding.