Chemistry · Periodicity of Elements and Periodic Properties

JEE Main 2024 — 29 January, Shift 2 — Question 70

The element having the highest first ionization enthalpy is:

Option A:
$\mathrm{Si}$
Option B:
$\mathrm{Al}$
Option C:
$\mathrm{N}$
Correct
Option D:
$\mathrm{C}$

Answer: C

Step-by-step solution

First ionisation enthalpy increases across a period due to increase in effective nuclear charge.

Among the given elements, $\mathrm{Al}$ and $\mathrm{Si}$ belong to period 3. $\mathrm{Si > Al}$ in ionisation enthalpy.

$\mathrm{C}$ and $\mathrm{N}$ belong to period 2. Ionisation enthalpy increases from $\mathrm{C}$ to $\mathrm{N}$ . $\mathrm{N}$ has half-filled configuration $2p^3$ , which is particularly stable. Thus, $\mathrm{N}$ has the highest first ionisation enthalpy.

Hence, the correct option is C.

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Exam: JEE Main 2024
Paper: 29 January, Shift 2
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 the other is labelled as Statement II. Statement I: Fluorine has most…

Answer: C

Step-by-step solution

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