Same chapter3 marksDifficulty: Medium
Why do transition metals and their compounds act as good catalysts?
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3 marksDifficulty: Medium
What is lanthanoid contraction and state two of its consequences.
Original Khojo Papers practice question — not from a past board paper.
Answer
Lanthanoid contraction is the steady decrease in the atomic and ionic radii of the lanthanoids with increasing atomic number, caused by the poor shielding of the nuclear charge by the 4f electrons. As a result the elements of the second and third transition series have almost identical sizes, so zirconium and hafnium are extremely hard to separate, and the basicity of the lanthanoid hydroxides falls across the series.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
It also explains the high density of the third transition series.
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