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MHT CET202615 April 2026Morning ShiftChemistryClassification of Elements and Periodicity in PropertiesActual

What happens to the size of atoms in p-block elements when we move from left to right in the same period?

Options

  1. ASize does not change
  2. BSize increases then decreases
  3. CSize increases
  4. DSize decreases

Correct answer

D. Size decreases

Step-by-step solution

As we move from left to right across a period, the atomic number increases, meaning the number of protons in the nucleus increases. The additional electrons are added to the same principal shell, so the shielding effect remains almost constant. This results in an increase in the effective nuclear charge ( Z_ eff ), which pulls the valence electrons closer to the nucleus. Consequently, the atomic size decreases from left to right in the same period. Answer: Size decreases

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