Hint:We have to know that the transition metal (or) element comes under the d block element. Some of the general features of transition metal such as variable oxidation state, formation of complex ions, colored ions and catalytic activity. Zinc and scandium are not taken as the transitions metals though they are members of the d block.
Complete step by step answer:
From the periodic table, we know that the transition metals are components present in groups 3-12. The transition metals are also called the d-block components. These components are described by their mostly involved d subshells in the free components or in their cations. The variety in the oxidation state of transitions components is because of the incomplete filling of d orbitals so that their oxidation states fluctuate from one another by solidarity.
The some important reason why transition metal plays the role of good catalyst is because they have the tendency to give electrons (or) withdraw electrons from the reagent based on the reaction’s nature. The tendency of transition metals to be a difference of oxidation states, the tendency to interchange between oxidation states and the tendency to produce complexes with the reagents and are good sources for electrons makes transition metals good catalysts.
The catalytic activity of transition metals and their compounds is because of the reasons described below:
The transition metals contain partially vacant d-orbital surface area for the molecules of the reactant.
The transition metals combine with molecules of reactant to produce transition states and lessen their activation energy.
They exhibit several oxidation states and give electrons to reactants, they produce complexes and lessen their energies.
Coordination complex as a compound that contains a central atom (ion) that is metallic and is called as the coordination centre. It is bounded by array bound molecules (or) ions known as ligands (or) complexing agents. Transition metals are coordination complexes. A coordination complex whose centre comprises an atom of metal is known as a metal complex of d block element.