Question

The actinoids exhibit more number of oxidation states in general than the lanthanoids. This is because

• A. The actinoids are more reactive than the lanthanoids.
• B. The 5f orbitals extend farther from the nucleus than the 4f orbitals.
• C. The 5f orbitals are more buried than the 4f orbitals
• D. There is a similarity between 4f and 5f orbitals in their angular part of the wave function

Answer 1

Answer: (B)

The 5f orbitals extend farther from the nucleus than the 4f orbitals.

Answer 2

The distance between the nucleus and 5¦ orbitals (actinides) is more than the distance between the nucleus and 4¦ orbitals (lanthanides). Hence the hold of nucleus on valence electron decreases in actinides. For this Statement-2 the actinoids exhibit more number of oxidation states in general.