Question

Give examples and suggest reasons for the following features of the transition metal chemistry:

(i)The lowest oxide of transition metal is basic, and the highest is amphoteric/acidic.

(ii) A transition metal exhibits the highest oxidation state in oxides and fluorides.

(iii) The highest oxidation state is exhibited in the oxoanions of a metal.

Answer 1

Part (i): The lowest oxide of transition metal is basic, and the highest is amphoteric/acidic

Lowest oxidation state:

In the case of a lower oxide of a transition metal, the metal atom has some electrons present in the valence shell of the metal atom are not involved in bonding. As a result, it can donate electrons and behave as a base.

Highest oxidation state:

In the case of a higher oxide of a transition metal, the metal atom does not have an electron in the valence shell for donation. As a result, it can accept electrons and behave as an acid.

Example: $MnO$ is basic and $M{n}_2{O}_7$ is acidic.

Part (ii): A transition metal exhibits the highest oxidation state in oxides and fluorides

• Oxygen and fluorine act as strong oxidizing agents because of their high electronegativities and small sizes.
• Hence, they bring out the highest oxidation states from the transition metals.
• For example, in $Os{F}_6$ and $V_2{O}_5$, the oxidation states of $Os$ and $V$ are $+6$ and $+5$ respectively.

Part (iii): The highest oxidation state is exhibited in the oxoanions of a metal.

• Oxygen is a strong oxidizing agent due to its high electronegativity and small size.
• So, oxo-anions of metal have the highest oxidation state.
• For example, in $Mn{O}_4^{-}$, the oxidation state of $Mn$ is $+7$.