NEET ChemistryNCERT Class 12d- and f-Block Elements

The d- and f-Block Elements: NEET questions with solutions

NEET tests the definition of a transition element, colour and spin-only magnetic moments from d-electron counts, oxidation-state and E° trends across the 3d series, the chemistry of K₂Cr₂O₇ and KMnO₄ in different media, and the lanthanoid contraction and its consequences. Marks are lost by counting electrons for the atom instead of the ion, by forgetting that permanganate behaves differently in neutral medium, and by mixing up Ce⁴⁺ (oxidant) with Eu²⁺ (reductant).

Revise first: NCERT notes for The d- and f-Block Elements

Questions

10 questions · answers after you pick

1Which of these aquated ions is colourless?Formation of coloured ionsEasySingle correct 2Zinc is placed in the d-block, yet it is not regarded as a transition element. Why?Electronic configuration of d-block elementsEasySingle correct 3As a result of the lanthanoid contraction, which pair of elements has almost identical atomic radii?Lanthanoid contractionEasySingle correct 4Which ion has a spin-only magnetic moment of about 3.87 BM?Magnetic propertiesMediumSingle correct 5Which 3d metal has a positive E°(M²⁺/M) value and therefore does not liberate hydrogen from dilute non-oxidising acids?Trends in M²⁺/M standard electrode potentialsMediumSingle correct 6When sodium hydroxide solution is added to an orange solution of potassium dichromate, the colour turns yellow. What change has occurred?Potassium dichromateMediumSingle correct 7Cr²⁺ and Mn³⁺ both have a d⁴ configuration, but they behave in opposite ways. Judge the Assertion (A) and the Reason (R) below.Trends in M³⁺/M²⁺ electrode potentialsMediumAssertion–Reason 8Most lanthanoids prefer the +3 state, but a few show +2 or +4. Which of the statements below are correct?The lanthanoidsMediumStatement based 9The product of an oxidation by permanganate or dichromate depends on the substrate and the medium. Match each reaction in List I with the…Potassium permanganate and dichromateHardMatch the following 10Which statement about the actinoids is INCORRECT?The actinoidsHardSingle correct

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