Question

A larger number of oxidation states are exhibited by the actinides than those by the lanthanides. The main reason being:

• A. more reactive nature of the actinides than the lanthanides
• B. $4f$ orbitals are more diffused than the $5f$ orbitals
• C. lesser energy difference between $5f$ and $6d$ orbitals than between $4f$ and $5d$ orbitals
• D. more energy difference between $5f$ and $6d$ orbitals than between $4f$ and $5d$ orbitals

Answer 1

Answer: (C)

lesser energy difference between $5f$ and $6d$ orbitals than between $4f$ and $5d$ orbitals

A larger number of oxidation states are exhibited by the actinides than those by the lanthanides because energy difference between $5f$ and $6d$ orbitals is less than that between $4f$ and $5d$ orbitals.

Hence, excitation of electrons can take place easily in actinides and thus, they exhibt a large number of oxidation states.

So, option C is correct.