Question

The main reason for larger number of oxidation state exhibited by the actinides than that corresponding lanthanide, is:

• A. lesser energy difference between 5f and 6d orbitals than between 4f and 5d-orbitals
• B. larger atomic size of actinides than the lanthanides
• C. more energy differenc between 5f and 6d orbitals than between 4f and 5d-orbitals
• D. greater reactive nature of the actinides than the lanthanides

Answer 1

Answer: (A)

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

Unlike lanthanides, actinides show a variety of oxidation states from +3 to +6 due to the very small energy gap between 5f, 6d, and 7s subshells.

The principal oxidation states are +3 and +4. The +3 oxidation state is the most stable. The +4 oxidation state is the most stable in Th and Pu. +5 in Pa and Np and +6 is seen in U. In actinides, the distributions of oxidation states are uneven.