Chapter 22, Problem 77A

Interpretation Introduction

(a)

Interpretation:

The reason for ions vary in charge is applied to transition metals needs to be explained.

Concept introduction:

In the periodic table, transition metals are those which have partially filled d sub-shell and they can form cations having incomplete d sub-shells. They belong to d-block in the periodic table including group 3 to 12.

Explanation of Solution

The transition metals can have ions vary with charge because there is more than 1 oxidation state stable for them. This is because transition metals have variable valences as there is similar energy of 3d and 4s orbitals. Due to this similar energy, electrons are able to bond from d shell as well. In other words, there are variable valences shown by transition elements due to participation of penultimate d shell electrons

Interpretation Introduction

(b)

Interpretation:

The reason for many of the solids to be colored for transition metals needs to be explained.

Concept introduction:

In the periodic table, transition metals are those which have partially filled d sub-shell and they can form cations having incomplete d sub-shells. They belong to d-block in the periodic table including group 3 to 12.

Explanation of Solution

The transition metals are colored due to the presence of unfilled or half filled d orbitals. The splitting of d orbital is explained by the crystal field theory. The d-orbital splits into a higher or lower orbital and electrons can jump from one orbital to other. When the electrons at ground state gets excited and jumps to higher energy states, they gain energy and when they come back to the ground state this energy is released with specific wavelength. This can fall in visible region of light and cause them to look colored.

Interpretation Introduction

(c)

Interpretation:

The reason for many of the solids to be hard for transition metals needs to be explained.

Concept introduction:

In the periodic table, transition metals are those which have partially filled d sub-shell and they can form cations having incomplete d sub-shells. They belong to d-block in the periodic table including group 3 to 12.

Explanation of Solution

In the transition metals, the electrons are far from nucleus. The electrons are easily available for bonding and forms strong metallic bonding. This is the reason for hardness of the transition metals. The strong metallic bonding cause transition metals to be tightly packed in the crystal lattice thus, they have high melting and boiling points.