Chemistry · Periodicity of Elements and Periodic Properties

JEE Main 2024 — 4 April, Shift 2 — Question 71

Given below are two statements, one is labelled as Statement I and the other is labelled as Statement II.

Statement I : The correct order of first ionization enthalpy values of Li,Na,F\mathrm{Li}, \mathrm{Na}, \mathrm{F} and Cl is Na<Li<Cl<F\mathrm{Na}<\mathrm{Li}<\mathrm{Cl}<\mathrm{F}.

Statement II : The correct order of negative electron gain enthalpy values of Li,Na,F\mathrm{Li}, \mathrm{Na}, \mathrm{F} and Cl is Na<Li<F<Cl\mathrm{Na}<\mathrm{Li}<\mathrm{F}<\mathrm{Cl}

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

  1. Option A:

    Both Statement I and Statement II are true

    Correct
  2. Option B:

    Both Statement I and Statement II are false

  3. Option C:

    Statement I is false but Statement II is true

  4. Option D:

    Statement I is true but Statement II is false

Answer: A

Step-by-step solution

Statement I is True: First ionization enthalpy decreases down a group and increases across a period. Therefore, the correct order of first ionization enthalpy is Na<Li<Cl<F\mathrm{Na < Li < Cl < F}.

Statement II is True: Electron gain enthalpy becomes more negative across a period and less negative down a group. Due to the small size of fluorine, chlorine has a more negative electron gain enthalpy than fluorine. Hence, the correct order of negative electron gain enthalpy is Na<Li<F<Cl\mathrm{Na < Li < F < Cl}.

Thus, both Statement I and Statement II are true (Option A).

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Chemistry
Chapter
Periodicity of Elements and Periodic Properties
Topic
Periodicity in Chemical Properties (Ionization Energy, Electron Affinity, Electronegativity)
Given below are two statements, one is labelled as Statement I and… | JEE Main 2024 PYQ with Solution · DhiX AI