Which forms interstitial compounds?

Which of the following sets correctly represents the increase in the paramagnetic property of the ions?

The correct order of ionisation energy is:

Of the following outer electronic configurations of atoms,the highest oxidation state is achieved by which one of them?

The colour of an electrolyte solution depends on

Assertion $(A)$: Transition elements have higher enthalpies of atomization.
Reason $(R)$: Large number of unpaired electrons present in transition elements facilitate strong interatomic interaction and strong bonding between atoms.