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4. d and f- block elements — Chemistry STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceChemistry4. d and f- block elements1 Mark
MCQ
Identify the incorrect statement in the following
  • A
    $d$ block element show irregular and erratic chemical properties among themselves.
  • B
    $La$ and $Lu$ have partially filled $d-$ orbital and no other partially filled orbital
  • C
    The chemistry of various Lanthanoids are similar
  • ✓
    $4f$ and $5f$ orbitals are equally shielded.
✓

Answer

Correct option: D.
$4f$ and $5f$ orbitals are equally shielded.
d
$4 f$ and $5 f$ orbitals are not equally shielded.$5$ are poorly shielded as $5 f$ orbitals are away from the nucleus.Also,$5$ has poor shielding effect than $4 f$ due to the large size of $f$-orbital, it is more diffused.

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