JEE Main 2025 Jan 24 Shift 2, Chemistry Q20: Periodicity In Atomic Properties

JEE Main2025Jan 24, Shift 2Chemistry

The successive 5 ionisation energies of an element are 800, 2427, 3658, 25024 and 32824 kJ/mol, respectively. By using the above values predict the group in which the above element is present :

A
Group 2
B
Group 13
C
Group 4
D
Group 14

Solution

Look at the successive jumps:

$I E_{1} = 800, I E_{2} = 2427, I E_{3} = 3658, I E_{4} = 25024, I E_{5} = 32824$ kJ/mol.

The increases from $I E_{1} \to I E_{2} \to I E_{3}$ are modest, but a huge jump occurs between $I E_{3}$ and $I E_{4}$ (3658 $\to$ 25024, about a $7 \times$ increase).

A large jump after the $n$ -th ionisation indicates that the $(n + 1)$ -th electron has to be removed from a much more tightly bound (inner) shell. Here, after losing 3 electrons the atom has reached a noble-gas-like core, so the element has 3 valence electrons.

An element with 3 valence electrons belongs to Group 13.

Correct option: (2)

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JEE Main 2025 Jan 24 Shift 2, Chemistry Q20: Periodicity In Atomic Properties

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