CBSE · Class 12 · Chemistry · The d-and f-Block ElementsLanthanoid contraction is caused by:
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Step-by-Step Solution
Lanthanoid contraction is the steady decrease in atomic and ionic radii across the lanthanoid series. It is primarily caused by the poor shielding effect of 4f electrons, which fails to compensate for the increasing nuclear charge.
Detailed Options Breakdown
Option : Poor shielding of 4f electrons (Correct Answer)
Correct choice. Refer to the step-by-step verified solution guidelines above for details.
Option 1: Increased shielding of 4f electrons
Incorrect choice. This distractor represents a common misunderstanding of the core principles of The d-and f-Block Elements.
Option 2: Decrease in nuclear charge
Incorrect choice. This distractor represents a common misunderstanding of the core principles of The d-and f-Block Elements.
Option 3: Addition of electrons to 5d orbital
Incorrect choice. This distractor represents a common misunderstanding of the core principles of The d-and f-Block Elements.
💡 Study Guide: This question tests core syllabus concepts from The d-and f-Block Elements. For formulas, key summaries, and mock exam reference guides, read the full The d-and f-Block Elements Revision Notes.