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Friday, 9 October

JEE Main 2024 · ChemistryMultiple choiceAssertion–reasonEasyConceptual

JEE Main 29 January 2024, Shift 1, Chemistry Q64

Question 64 of 90 in this shift, Chemistry question 4 of 30, Section A.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : The first ionisation enthalpy decreases across a period. Reason R : The increasing nuclear charge outweighs the shielding across the period. In the light of the above statements, choose the most appropriate from the options given below :
  1. (1)Both A and R are true and R is the correct explanation of A
  2. (2)Both A and R are true but R is NOT the correct explanation of A
  3. (3)A is true but R is false
  4. (4)A is false but R is trueOfficial answer

Official answer

Option 4

NTA final key.

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

Same idea in other shifts

Asked 7× in all
  1. 2 Apr 2026, Shift 2 · Q59Given below are two statements: Statement I: The second ionization enthalpy of B, Al and Ga is in the order of B > Al > Ga. Statement II:…MediumSingle correct
  2. 6 Apr 2026, Shift 1 · Q71First and second ionization enthalpies of lithium are 520 kJ mol−1^{-1} and 7297 kJ mol−1^{-1} respectively. Energy required to convert…EasyNumerical value
  3. 6 Apr 2026, Shift 2 · Q58In a period, the first ionisation enthalpy of the element at extreme left and the negative electron gain enthalpy of the extreme right…EasySingle correct
  4. 8 Apr 2026, Shift 2 · Q58Match List - I with List - II. List - I (Electronic configuration of neutral atom (where n = 2)) | List - II (1st^{st} Ionization Energy…MediumMatch the list
  5. 3 Apr 2025, Shift 1 · Q60Which of the following statements are correct ? A. The process of adding an electron to a neutral gaseous atom is always exothermic. B.…MediumOther
  6. 8 Apr 2025, Shift 2 · Q56The atomic number of the element from the following with lowest 1st^{st} ionisation enthalpy is :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.