Chapter 8.3, Problem 1RCF

(a)

Interpretation Introduction

Interpretation: Size of $Be$ and $Ba$ has to be compared.

Concept Introduction:

Atomic radius is the distance between the atomic nucleus and outermost electron of an atom. From the atomic radius, the size of atoms can be visualized.

Along the period, the valence electron is added to the same shell and thus attraction by the nucleus gets stronger. Therefore, atomic radii reduces from left to right in the periodic table

Group 2A in the periodic table contains 2 valence electrons and the outer electronic configuration is ${\text{ns}}^{\text{2}}$.

(b)

Interpretation Introduction

Interpretation: Size of $Al$ and $S$ has to be compared.

Concept Introduction:

Atomic radius is the distance between the atomic nucleus and outermost electron of an atom. From the atomic radius, the size of atoms can be visualized.

Along the period, the valence electron is added to the same shell and thus attraction by the nucleus gets stronger. Therefore, atomic radii reduces from left to right in the periodic table

(c)

Interpretation Introduction

Interpretation: Size of ${}^{12}C$ and ${}^{13}C$ has to be compared.

Concept Introduction:

Atomic radius is the distance between the atomic nucleus and outermost electron of an atom. From the atomic radius, the size of atoms can be visualized.

Isotopes of an element have different mass number (different number of neutrons).