Assertion (A):
“Highest oxidation state of Mn is +7 in most of the transition elements.”
This is false.
While Manganese does show a maximum oxidation state of +7 (e.g., in permanganate), this is not true for most transition elements.
Many transition metals show maximum oxidation states different from +7.
Some even exceed +7 (e.g., Ru and Os can reach +8).
So the statement is incorrect.
Reason (R):
“Transition metals exhibit variable oxidation states.”
This is true.
This happens because:
(n–1)d and ns orbitals have comparable energies.
Both can participate in bonding.
Since Assertion is false but Reason is true.