Chapter 12, Problem 155AE

Interpretation Introduction

Interpretation:Indicated table should be completed with appropriate choices between $\text{K}$ and $\text{Cs}$ ,between $\text{Te}$ and $\text{Br}$ , between $\text{Ge}$ and $\text{Se}$ for more favorable electron affinity that is exothermic, for more exothermic electron affinity, higher ionization energy, and larger atomic size.

  $\begin{array}{cccc}& \begin{array}{l}\text{K }\\ \text{and Cs}\end{array}& \begin{array}{l}\text{Te and}\\ \text{ Br}\end{array}& \begin{array}{l}\text{Ge }\\ \text{and Se}\end{array}\\ \begin{array}{l}\text{More }\\ \text{favorable }\\ \text{electron}\\ \text{ affinity}\end{array}& & & \\ \begin{array}{l}\text{Higher }\\ \text{ionization}\\ \text{ energy}\end{array}& & & \\ \text{Larger size}& & & \end{array}$

Concept introduction:In order to remove the electron situated in outermost shell certain minimum energy must be imparted so as to convert an atom to gaseous species. The energy thus imparted represents ionization energy.

The magnitude of ionization energy is determined by how effectively valence electron is held by the nucleus. If the outermost shell has, for instance, one or two electronsthat require very minimum ionization energy because they can attain the noble gas configuration upon loss of those electrons.

As one moves from top to bottom the shells expands and size increases, while it decreases as one move along the period.