Question

Which of the following properties is NOT of actinoids?

• A. Hydroxides of these are more basic in nature than lanthanoids
• B. Some of the ions of these are fairly coloured
• C. Binding energy of 5f orbitals is lower than 4f orbitals
• D. These have greater tendency to form complexes

Hint:

Actinoids usually show intense colours and variable oxidation states due to involvement of 5f orbitals.

Answer 1

The Correct Option is B

Step 1: Recall general properties of actinoids.
Actinoids involve filling of 5f orbitals and show complex behavior due to variable oxidation states and poor shielding effect.
Step 2: Analyze each option.
(A) Actinoid hydroxides are more basic than lanthanoids — this is true due to higher ionic character.
(B) Actinoid ions are generally intensely coloured due to f–f transitions, not fairly coloured — this statement is incorrect.
(C) 5f orbitals have lower binding energy than 4f orbitals — true.
(D) Actinoids show greater tendency to form complexes due to smaller size and higher charge — true.
Step 3: Conclusion.
Option (B) is NOT a property of actinoids.