Chapter 20, Problem 20.47SP

Interpretation Introduction

Interpretation

The metals which have only one oxidation state should be determined from the given metals.

Concept introduction:

Transition element is one which can form one or more stable ions with a partially occupied d-subshell. Most of the transition elements are metals and majority of elements exists in various oxidation states also. 

Oxidation state is the difference between the numbers of electrons associated with an atom in a compound.

In ions the oxidation state is the ionic charge

In covalent compounds the oxidation state corresponds to the formal charge.

In elements oxidation state is assumed to exist in the zero oxidation state.

The variable oxidation state of transition elements is due to their small energy difference between the 4s and 3d subshells.

Some elements with variable oxidation states are listed below,

$\begin{array}{cc}\text{Elements}& \text{Oxidation}\text{state}\\ V& \text{+2,+3,+4}\text{and +5}\\ \text{Mn}& \text{+2,+3,+4,+5}\text{and}\text{+6}\\ \text{Cr}& \text{+2,+3,+4,+5}\text{and}\text{+6}\\ Co& \text{+2,+3,+4}\text{and +5}\\ Al& \text{+1,+2}\text{and}\text{+3}\end{array}$