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JEE Main 2025 Jan 24 Shift 2, Chemistry Q15: Periodicity In Atomic Properties

JEE Main2025Jan 24, Shift 2Chemistry
Q.

Given below are two statements :

Statement (I) : The first ionization energy of Pb is greater than that of Sn

Statement (II) : The first ionization energy of Ge is greater than that of Si.

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

  1. A

    Statement I is true but Statement II is false

  2. B

    Both Statement I and Statement II are false

  3. C

    Statement I is false but Statement II is true

  4. D

    Both Statement I and Statement II are true

Solution

For Group-14 elements the first ionisation energies (kJ/mol) are roughly:

From these values:

  •   — caused by the poor shielding of the filled and subshells in Pb, which leads to a higher effective nuclear charge (inert-pair effect). Statement I is correct.
  • , so is in fact less than . Statement II is incorrect.

Correct option: (1)

Concept behind this question

Periodicity In Atomic PropertiesNotes, formulas and examples →

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