Ionic size (isoelectronic series): Arrange the ionic radii of N³⁻, O²⁻, F⁻, and Na⁺ in the correct order. All have 10 electrons; size depends on nuclear charge Z. Choose the correct option.
IIT JEE
Chemistry
Difficulty: Easy
Choose an option
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ANa⁺ > F⁻ > O²⁻ > N³⁻
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BN³⁻ > O²⁻ > F⁻ > Na⁺
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CF⁻ > O²⁻ > N³⁻ > Na⁺
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DO²⁻ > N³⁻ > F⁻ > Na⁺
Answer
Correct Answer: N³⁻ > O²⁻ > F⁻ > Na⁺
Explanation
Concept/ApproachFor an isoelectronic series (same electrons), ionic radius decreases with increasing nuclear charge (Z). Z increases from N (7) → O (8) → F (9) → Na (11). Hence size: N³⁻ > O²⁻ > F⁻ > Na⁺.