JEE Main 2021 · ChemistryMultiple choiceSingle correctEasyData or graph

JEE Main 16 March 2021, Shift 2, Chemistry Q36

Question 36 of 90 in this shift, Chemistry question 6 of 30, Section A.

Identify the elements X and Y using the ionisation energy values given below : Ionization energy (kJ/mol) 1st 2nd X 495 4563 Y 731 1450

(1)X = Na ; Y = MgOfficial answer
(2)X = Mg ; Y = Na
(3)X = F ; Y = Mg
(4)X = Mg ; Y = F

Official answer

Option 1

NTA final key.

Chapter: Classification of Elements and Periodicity in Properties
Topic: Periodic Trends
Idea tested: Successive Ionization Enthalpy Jumps

Same idea in other shifts

Asked 4× in all

2 Apr 2026, Shift 1 · Q59Given below are two statements : Statement (I) : The first ionisation enthalpy of the elements Na, Mg, Cl and Ar follows the order Na > Mg…MediumTwo statements
4 Apr 2026, Shift 2 · Q57The $1^{\text{st}}$ ionization enthalpy for Mg is +737 kJ/mol. The most probable estimated value of the $2^{\text{nd}}$ ionization…EasySingle correct
9 Jan 2020, Shift 2 · Q32The first and second ionisation enthalpies of a metal are 496 and 4560 kJ mol $^{-1}$ , respectively. How many moles of HCl and…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 42 of the 174 JEE Main shifts held from 2017 to 2026.