NEET2026ChemistryChapterActual
Which of the following is a direct consequence of the lanthanoid contraction?
Options
- AThe basic character of the lanthanoid hydroxides increases steadily from La(OH)₃ to Lu(OH)₃ .
- BThe separation of lanthanoids from their mixture is highly simplified due to significant differences in their
- CThe atomic radii of the elements of the second transition series (4d) are almost identical to those of the cor
- DThe covalent character of the Ln-OH bond decreases progressively from La³⁺ to Lu³⁺ .
Correct answer
C. The atomic radii of the elements of the second transition series (4d) are almost identical to those of the cor
Step-by-step solution
The lanthanoid contraction refers to the steady decrease in atomic and ionic radii across the lanthanoid series due to the poor shielding effect of the 4f electrons. A direct consequence of this contraction is that the atomic radii of the elements of the third transition series ( 5d ) become almost identical to those of the corresponding elements of the second transition series ( 4d ). For example, the atomic radii of Zr ( 160 pm) and Hf ( 159 pm) are nearly the same. Regarding the other options: As the size of the