The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are : A. $\mathrm{Cr^{2+}}$ B. $\mathrm{Fe^{2+}}$ C. $\mathrm{Fe^{3+}}$ D. $\mathrm{Co^{2+}}$ E. $\mathrm{Mn^{3+}}$ Choose the correct answer from the options given below:

JEE Main 2025 · ChemistryMultiple choiceOtherEasyCalculation

JEE Main 3 April 2025, Shift 1, Chemistry Q62

Question 62 of 75 in this shift, Chemistry question 12 of 25, Section A.

The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are : A.

\mathrm{Cr^{2+}}

\mathrm{Fe^{2+}}

\mathrm{Fe^{3+}}

\mathrm{Co^{2+}}

\mathrm{Mn^{3+}}

Choose the correct answer from the options given below:

(1)A, B and E OnlyOfficial answer
(2)A, D and E Only
(3)B and E Only
(4)A, C and E Only

Official answer

Option 1

NTA final key.

Chapter: The d- and f-Block Elements
Topic: d-Block Elements
Idea tested: Spin-only Magnetism

Same idea in other shifts

Asked 6× in all

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8 Apr 2025, Shift 2 · Q58The correct decreasing order of spin only magnetic moment values (BM) of $\mathrm{Cu^+}$ , $\mathrm{Cu^{2+}}$ , $\mathrm{Cr^{2+}}$ and…EasySingle correct
6 Apr 2024, Shift 2 · Q86Among $\mathrm{VO_2^+}$ , $\mathrm{MnO_4^-}$ and $\mathrm{Cr_2O_7^{2-}}$ , the spin-only magnetic moment value of the species with least…MediumNumerical value
8 Apr 2024, Shift 1 · Q86The 'spin only' magnetic moment value of $\mathrm{MO_4^{2-}}$ is ____________ BM. (Where M is a metal having least metallic radii. among…MediumNumerical value

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.