D Block Elements

Step 1: Concept
The maximum oxidation state of a d-block element is generally equal to the sum of the and electrons.
Step 2: Calculation
(A) (but typically doesn't reach +10)
(B)
(C)
(D)
Step 3: Analysis
Configuration (D) represents Manganese (Mn), which shows a maximum oxidation state of +7 (as in ).
Step 4: Conclusion
achieves the highest common oxidation state among the options.
Final Answer: (D)

Step 1: Understanding the Concept:
Transition metals (d-block elements) are known for their exceptional catalytic properties.

Step 2: Detailed Explanation:
d-block elements (transition metals) possess vacant d-orbitals and variable oxidation states. These properties allow them to adsorb reactants, form intermediates, and lower the activation energy of reactions, making them excellent catalysts. Examples include Fe (Haber process), Ni (hydrogenation), and Pt (catalytic converters). s-block and p-block elements are generally less effective as catalysts, and f-block elements (lanthanides/actinides) are used in specific catalytic processes but are not the most common.

Step 3: Final Answer:
Metals used as catalysts typically belong to the d-block, which corresponds to option (C).