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NEET CHEMISTRYThe d-and f-Block ElementsEasy

Question

The reason for lanthanoid contraction is:

A

Negligible screening effect of 'f' orbitals

B

Increasing nuclear charge

C

Decreasing nuclear charge

D

Decreasing screening effect

Step-by-Step Solution

Lanthanoid contraction is the gradual decrease in the atomic and ionic radii of lanthanoids with an increase in atomic number. As we move along the lanthanoid series, the new electrons are added to the inner 4f4f subshell. The 4f4f electrons have a highly diffused shape and provide very poor (negligible) shielding or screening effect. As the nuclear charge increases, the imperfect shielding of the 4f4f electrons is inadequate to counteract the increased nuclear pull. Consequently, the valence electrons are pulled more strongly towards the nucleus, leading to a contraction in size.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from The d-and f-Block Elements. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYThe d-and f-Block Elementsreasonlanthanoidcontraction

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The incorrect statement among the following is:

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