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JEE Main 2025 Jan 29 Shift 1, Chemistry Q20: Periodicity In Atomic Properties

JEE Main2025Jan 29, Shift 1Chemistry
Q.

Given below are two statements :

Statement (I) : The radii of isoelectronic species increases in the order.

Statement (II) : The magnitude of electron gain enthalpy of halogen decreases in the order.

In the light of the above statements, choose the most appropriate answer from the options given below :

  1. A

    Statement I is incorrect but Statement II is correct

  2. B

    Both Statement I and Statement II are incorrect

  3. C

    Statement I is correct but Statement II is incorrect

  4. D

    Both Statement I and Statement II are correct

Solution

Statement I: All four species share 10 electrons. For isoelectronic ions, the ionic radius is determined by the nuclear charge: the higher , the smaller the radius. The order of is , so radii increase as . Correct.

Statement II: Fluorine's small size produces strong electron-electron repulsion in the compact 2p subshell, making smaller than . The accepted order of magnitudes is . Correct.

Both statements are correct.

Concept behind this question

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