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JEE Main202628 January 2026Morning ShiftChemistryClassification of Elements and Periodicity in PropertiesActual

In period 4 of the periodic table, the elements with highest and lowest atomic radii are respectively.

Options

  1. ARb & Br
  2. BK & Se
  3. CK ~ &~ Br
  4. DNa ~ &~ Cl

Correct answer

C. K ~ &~ Br

Step-by-step solution

In period 4, atomic radii decrease from left to right as nuclear charge increases while electron shell remains constant. K (potassium) is at the extreme left of period 4 metals and has the highest atomic radius. Br (bromine) is near the right end as a nonmetal and has the lowest atomic radius in this period. Therefore, the elements with highest and lowest atomic radii in period 4 are K and Br respectively.

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