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NEETChemistryd and f Block Elements

What is the factor responsible for the lanthanoid contraction?

Options

  1. AThe imperfect shielding of one 4f electron by another.
  2. BThe increase in atomic mass.
  3. CThe filling of 5d orbitals before 4f orbitals.
  4. DThe decrease in metallic radius.

Correct answer

A. The imperfect shielding of one 4f electron by another.

Step-by-step solution

The lanthanoid contraction is caused by the imperfect shielding of one 4f electron by another.

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