JEE Main 2021 · ChemistryMultiple choiceSingle correctEasyApplication

JEE Main 4 August 2021, Shift 1, Chemistry Q35

Question 35 of 90 in this shift, Chemistry question 5 of 30, Section A.

The correct order of first ionization enthalpy is :

(1)Be > B > C > N > O
(2)O > N > C > B > Be
(3)N > O > C > Be > BOfficial answer
(4)N > O > C > B > Be

Official answer

Option 3

NTA final key.

Chapter: Classification of Elements and Periodicity in Properties
Topic: Periodic Trends
Idea tested: p-Block Ionization Enthalpy Inversions

Same idea in other shifts

Asked 8× in all

4 Apr 2024, Shift 2 · Q67The correct order of the first ionization enthalpy isMediumSingle correct
11 Apr 2023, Shift 1 · Q64For elements B, C, N, Li, Be, O and F, the correct order of first ionization enthalpy isEasySingle correct
25 Jul 2022, Shift 2 · Q66The first ionization enthalpies of Be, B, N and O follow the orderEasySingle correct
27 Jul 2022, Shift 2 · Q66Outermost electronic configurations of four elements A, B, C, D are given below : (A) $3s^2$ (B) $3s^23p^1$ (C) $3s^23p^3$ (D) $3s^23p^4$ …MediumSingle correct
29 Jul 2022, Shift 1 · Q64The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and 786 kJ $\mathrm{mol^{-1}}$ . The first ionization enthalpy…MediumSingle correct
29 Jun 2022, Shift 2 · Q66Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The first ionization…EasyAssertion–reason
26 Feb 2021, Shift 1 · Q33Match List-I with List-II. List-I (Electronic configuration of elements) | List-II ( $\Delta_i H$ in kJ mol $^{-1}$ ) (a) $1s^2\ 2s^2$ | (i)…MediumMatch the list

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.