JEE Main 2021ChemistryClassification of Elements and Periodicity in PropertiesEasyMCQ

JEE Main 2021 — Classification of Elements and Periodicity in Properties Question with Solution

JEE Main 2021 (25 Jul Shift 1)

Question

The ionic radii of K+,Na+,Al3+ and Mg2+ are in the order :

Choose an option

Show full solutionCorrect option: C
Correct answer
CAl3+<Mg2+<Na+<K+

Step-by-step explanation

Al3+,Mg2+ and Na+ are isoelectronic ionic species. For monatomic ionic isoelectronic species as positive charge increases ionic size decreases.

The order of size of Na+& K+ is Na+<K+,

∴ Increasing order of ionic radii:  Al3+<Mg2+<Na+<K+

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About this question

This is a previous-year question from JEE Main 2021, covering the Classification of Elements and Periodicity in Properties chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.