JEE Main 2021 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 18 March 2021, Shift 1, Chemistry Q34

Question 34 of 90 in this shift, Chemistry question 4 of 30, Section A.

The ionic radius of

\mathrm{Na^+}

ion is 1.02 Å. The ionic radii (in Å) of

\mathrm{Mg^{2+}}

and

\mathrm{Al^{3+}}

, respectively, are :

(1)0.85 and 0.99
(2)0.72 and 0.54Official answer
(3)0.68 and 0.72
(4)1.05 and 0.99

Official answer

Option 2

NTA final key.

Chapter: Classification of Elements and Periodicity in Properties
Topic: Periodic Trends
Idea tested: Isoelectronic Species Radii Comparison

Same idea in other shifts

Asked 10× in all

5 Apr 2024, Shift 1 · Q66The statement(s) that are correct about the species $\mathrm{O^{2-}}$ , $\mathrm{F^-}$ , $\mathrm{Na^+}$ and $\mathrm{Mg^{2+}}$ . (A) All are…EasyOther
1 Feb 2024, Shift 1 · Q65In case of isoelectronic species the size of $\mathrm{F^-}$ , Ne and $\mathrm{Na^+}$ is affected by :EasySingle correct
15 Apr 2023, Shift 1 · Q87The total number of isoelectronic species from the given set is __________. $\mathrm{O^{2-}, F^-, Al, Mg^{2+}, Na^+, O^+, Mg, Al^{3+}, F}$ EasyNumerical value
27 Jun 2022, Shift 1 · Q65Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The ionic radii…EasyAssertion–reason
27 Jun 2022, Shift 2 · Q65The correct order of increasing ionic radii isEasySingle correct
27 Aug 2021, Shift 2 · Q32The correct order of ionic radii for the ions, $\mathrm{P^{3-}}$ , $\mathrm{S^{2-}}$ , $\mathrm{Ca^{2+}}$ , $\mathrm{K^{+}}$ ,…EasySingle correct
25 Jul 2021, Shift 1 · Q33The ionic radii of $\mathrm{K^+}$ , $\mathrm{Na^+}$ , $\mathrm{Al^{3+}}$ and $\mathrm{Mg^{2+}}$ are in the order :EasySingle correct
25 Jul 2021, Shift 2 · Q34The ionic radii of $\mathrm{F^{-}}$ and $\mathrm{O^{2-}}$ respectively are 1.33 Å and 1.4 Å, while the covalent radius of N is 0.74 Å. The…EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.