The statement(s) that are correct about the species \(\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}^{+}\)and \(\mathrm{Mg}^{2+}\). (A) All are isoelectronic (B) All have the same nuclear charge (C) \(\mathrm{O}^{2-}\) has the largest ionic radii (D) \(\mathrm{Mg}^{2+}\) has the smallest ionic radii Choose the most appropriate answer from the options given below :

JEE Main · 2024 · 05 Apr 2024 · Shift 1 · Classification of Elements and Periodicity

The statement(s) that are correct about the species

O^{2 -}, F^{-}, Na^{+}

and

Mg^{2 +}

.
(A) All are isoelectronic
(B) All have the same nuclear charge
(C)

O^{2 -}

has the largest ionic radii
(D)

Mg^{2 +}

has the smallest ionic radii

Choose the most appropriate answer from the options given below :

(A)(B), (C) and (D) only
(B)(A), (B), (C) and (D)
(C)(C) and (D) only
(D)(A), (C) and (D) only✓ Correct

Answer: (D)

Solution

O^{2 -}, F^{-}, N a^{+}, M g^{2 +}

each have 10 electrons, so all are isoelectronic — (A) true. They have different nuclear charges (8, 9, 11, 12), so (B) is false. For isoelectronic species, larger nuclear charge means smaller radius, giving

O^{2 -} > F^{-} > N a^{+} > M g^{2 +}

O^{2 -}

largest (C true) and

M g^{2 +}

smallest (D true). Correct set: (A), (C) and (D).

JEE Main · 2024 · 05 Apr 2024 · Shift 1 · Single correct option

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JEE Main · 2024 · 05 Apr 2024 · Shift 1 · Classification of Elements and Periodicity

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