d & f Block Elements JEE Main PYQs, 2020 to 2025

The correct decreasing order of spin only magnetic moment values (BM) of Cu⁺, Cu²⁺, Cr²⁺ and Cr³⁺ ions is :

The first transition series metal ' $M$ ' has the highest enthalpy of atomisation in its series. One of its aquated ion $\left(\mathrm{M}^{\mathrm{n}+}\right)$ exists in green colour. The nature of the oxide formed by the above $\mathrm{M}^{\mathrm{n}+}$ ion is:

Given below are two statements:

Statement I: In the oxalic acid vs $\mathrm{KMnO}_4$ (in the presence of dil $\mathrm{H}_2 \mathrm{SO}_4$ ) titration the solution needs to be heated initially to $60^{\circ} \mathrm{C}$, but no heating is required in Ferrous ammonium sulphate (FAS) vs $\mathrm{KMnO}_4$ titration (in the presence of dil $\mathrm{H}_2 \mathrm{SO}_4$)

Statement II: In oxalic acid vs $\mathrm{KMnO}_4$ titration, the initial formation of $\mathrm{MnSO}_4$ takes place at high temperature, which then acts as catalyst for further reaction. In the case of FAS vs $\mathrm{KMnO}_4$, heating oxidizes $\mathrm{Fe}^{2+}$ into $\mathrm{Fe}^{3+}$ by oxygen of air and error may be introduced in the experiment.

In the light of the above statements, choose the correct answer from the options given below

Which of the following ions is the strongest oxidizing agent? (Atomic Number of $\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{~Tb}=65, \mathrm{Lu}=71$)

The IUPAC nomenclature of an element with electronic configuration [Rn] $5 \mathrm{f}^{14} 6 \mathrm{d}^{1} 7 \mathrm{s}^{2}$ is :