JEE Main 2021ChemistryClassification of Elements and Periodicity in PropertiesMediumMCQ

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

JEE Main 2021 (24 Feb Shift 1)

Question

Consider the elements Mg, Al,S,P and Si, the correct increasing order of their first ionisation enthalpy is:

Choose an option

Show full solutionCorrect option: A
Correct answer
AAl<Mg<Si<S<P

Step-by-step explanation

In general from left to right in a period, ionisation enthalpy increases due to effective nuclear charge increases. but due to extra stability of half filled and full filled electronic configuration, required ionisation enthalpy is more from neighbouring elements.
i.e. first ionisation enthalpy order is

Al<Mg<Si<S<P

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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.