Chapter 8.3, Problem 8.3AFP

(a)

Interpretation Introduction

Interpretation:

The following elements are to be arranged in the order of the increasing size.

$\text{Se,}\text{}\text{Br,}\text{Cl}$

Concept introduction:

Atomic size is the distance from the nucleus to the valence shell where the electrons are located. It is difficult to be measured because of the lack of definite boundary.

The atomic size increases from top to bottom in a group because of the increase in the number of shells.

Along the period, the atomic size decreases because the effective nuclear charge increases.

(b)

Interpretation Introduction

Interpretation:

The following elements are to be arranged in the order of the increasing size.

$\text{I,}\text{Xe,}\text{Ba}$

Concept introduction:

Atomic size is the distance from the nucleus to the valence shell where the electrons are located. It is difficult to be measured because of the lack of a definite boundary.

The atomic size increases from top to bottom in a group because of the increase in the number of shells.

Along the period, the atomic size decreases because the effective nuclear charge increases.