Question

Transition metals are good catalytic agents. Why?

Answer 1

Transition metals are metallic elements with valence electrons in two shells rather than one, such as chromium, iron, and nickel. The chemical characteristics of an atom are determined by a single electron called a valence electron. Transition metals are excellent metal catalysts because they lend and absorb electrons from other molecules quickly. A catalyst is a chemical material that, when introduced to a chemical reaction, enhances the rate of reaction without changing the thermodynamics of the reaction.

Complete answer:
The fact that transition metals can lend or take electrons from the reagent, depending on the nature of the reaction, is the most essential reason they are good catalysts. Transition metals are useful catalysts because of their capacity to be in a range of oxidation states, their ability to switch between oxidation levels, their ability to form complexes with reagents, and their ability to be a good source of electrons.
$S{{c}^{3+}}$ , the scandium ion, is not a transition metal because it lacks d-electrons. Because the d-orbital of the zinc ion, $Z{{n}^{2+}}$ , is completely filled, it is not a transition metal. Transition metals must have enough d-electrons to spare, and their oxidation states are varied and interchangeable. Copper, with its varied oxidation states $C{{u}^{2+}}$ and $C{{u}^{3+}}$ , is an excellent example of a transition metal. The metal's imperfect d-orbital allows it to facilitate electron exchange. Transition metals are excellent catalysts because they can easily give and accept electrons. The ability of a metal to form chemical bonds is determined by its oxidation state.
Transition metals interact with the reagent by creating complexes with it. To supply electrons to the transition state of the reaction, the transition metals in the metal complexes undergo oxidation or reduction reactions. If a surplus of electrons builds up, the transition metals can hold the excess electron density, allowing the process to proceed. The ability of transition metals to act as catalysts is also influenced by the metal's and the transition metal complex's absorption or adsorption capabilities.

Note:
In the periodic table, transition metals are frequently mistaken for "d-block" metals. Despite the fact that transition metals are found in the d-block of the periodic table, not all d-block metals are transition metals. Scandium and zinc, for example, are not transition metals despite being d-block elements. To be a transition metal, a d-block element must have an incompletely filled d-orbital.