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MHT CET202618 April 2026Morning ShiftChemistryd and f Block ElementsActual

Which actinoid from following has smallest ionic size in +3 state?

Options

  1. APa
  2. BCm
  3. CFm
  4. DLr

Correct answer

D. Lr

Step-by-step solution

In the actinoid series, as the atomic number increases from Actinium (Ac) to Lawrencium (Lr), there is a gradual decrease in the size of atoms or M³⁺ ions. This phenomenon is known as actinoid contraction, which is due to the poor shielding effect of the 5f electrons. The given elements belong to the actinoid series with the following atomic numbers: Pa ( Z = 91 ) Cm ( Z = 96 ) Fm ( Z = 100 ) Lr ( Z = 103 ) Since Lawrencium (Lr) has the highest atomic number among the given options, it experiences the maximum actin

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