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The d & f Block Elements — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryThe d & f Block Elements1 Mark
MCQ
The Lanthanoid contraction refers to decrease in the:
  • A
    Valence electrons of the Lanthanide series.
  • ✓
    Ionic radius of the series.
  • C
    The density of the series.
  • D
    Nuclear mass of the series.
✓

Answer

Correct option: B.
Ionic radius of the series.
The Lanthanoid contraction refers to decrease in the ionic radius of the series. It is a reduction in atomic/ionic size with increase in atomic number. This is due to poor shielding of $4f$ electrons.

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