Start learning →

OJEE d- and f-Block Elements — practice questions

Explore 54 free d- and f-Block Elements questions in OJEE Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise d- and f-Block Elements with Quill →

d- and f-Block Elements questions and exercises with answers

Showing questions 1–30 of 54.

The general outer electronic configuration of d-block elements is:Read the answer and worked solution →The electronic configuration of Cr (Z = 24) is:Read the answer and worked solution →Which 3d transition element exhibits the largest number of oxidation states?Read the answer and worked solution →The most stable oxidation state of Sc is:Read the answer and worked solution →The spin-only magnetic moment μ in BM for n unpaired electrons is given by:Read the answer and worked solution →Calculate the spin-only magnetic moment of a divalent ion of Mn (Z = 25):Read the answer and worked solution →Which of the following ions is colourless and diamagnetic?Read the answer and worked solution →The oxidation state of chromium in both CrO₄²⁻ and Cr₂O₇²⁻ is:Read the answer and worked solution →Potassium dichromate (K₂Cr₂O₇) is prepared from which ore?Read the answer and worked solution →In KMnO₄, the oxidation state of Mn is:Read the answer and worked solution →The most common oxidation state of lanthanoids is:Read the answer and worked solution →Which lanthanoid is well known to exhibit the +4 oxidation state in aqueous solution as a strong oxidising agent?Read the answer and worked solution →The general electronic configuration of actinoids is:Read the answer and worked solution →Which of the following ions is NOT coloured in aqueous solution?Read the answer and worked solution →Among Sc²⁺, V³⁺, Mn²⁺ and Zn²⁺, which is paramagnetic with **5** unpaired electrons?Read the answer and worked solution →d-block elements have differentiating electrons in:Read the answer and worked solution →f-block elements include:Read the answer and worked solution →Compounds of transition metals are usually:Read the answer and worked solution →Why does Zn²⁺ have no color (Zn = d¹⁰)?Read the answer and worked solution →Which transition metal forms unstable highest oxidation state +7?Read the answer and worked solution →Magnetic moment of complex with 5 unpaired d-electrons (high spin):Read the answer and worked solution →K₂Cr₂O₇ (potassium dichromate) is a strong:Read the answer and worked solution →Coordination number of Ag in [Ag(CN)₂]⁻:Read the answer and worked solution →Oxidation state of Cu in [Cu(NH₃)₄]²⁺:Read the answer and worked solution →Magnetic moment of [Fe(H₂O)₆]³⁺ (Fe³⁺ is d⁵, weak field H₂O → high spin):Read the answer and worked solution →Number of unpaired electrons in [Mn(CN)₆]³⁻ (Mn(III), d⁴, strong field CN⁻):Read the answer and worked solution →Eu²⁺ is more stable than other Ln²⁺ because:Read the answer and worked solution →Why is Sc³⁺ colorless?Read the answer and worked solution →Magnetic susceptibility of Fe³⁺ vs Fe²⁺ in high-spin complexes:Read the answer and worked solution →NEET · Chemistry · Lanthanide or ActinideRead the answer and worked solution →

Worked practice questions

The general outer electronic configuration of d-block elements is:

  1. nd¹⁻¹⁰ (n+1)s¹⁻²
  2. (n−1)d⁰ ns²
  3. (n−1)d¹⁻¹⁰ ns¹⁻²
  4. ns¹⁻² np¹⁻⁶
Show answer and solution

Correct answer: C. (n−1)d¹⁻¹⁰ ns¹⁻²

**(n−1)d¹⁻¹⁰ ns¹⁻²** (except Pd, 4d¹⁰5s⁰). The penultimate d orbital is progressively filled across each row ns has 1–2 electrons.

Open this question →

The electronic configuration of Cr (Z = 24) is:

  1. [Ar] 3d³ 4s³
  2. [Ar] 3d⁵ 4s¹
  3. [Ar] 3d⁶ 4s⁰
  4. [Ar] 3d⁴ 4s²
Show answer and solution

Correct answer: B. [Ar] 3d⁵ 4s¹

**Cr: [Ar] 3d⁵ 4s¹** (not 3d⁴ 4s²). The half-filled 3d⁵ + half-filled 4s¹ configuration provides **extra stability** from exchange energy and symmetry. **Similar exception in Cu:** 3d¹⁰ 4s¹ (not 3d⁹ 4s²).

Open this question →

Which 3d transition element exhibits the largest number of oxidation states?

  1. Zn (only +2)
  2. Sc (only +3)
  3. Fe (+2 and +3)
  4. Mn — +2, +3, +4, +5, +6, +7 (six states; widest range)
Show answer and solution

Correct answer: D. Mn — +2, +3, +4, +5, +6, +7 (six states; widest range)

**Manganese** exhibits the **widest range of oxidation states (+2 to +7)** in the 3d series. This is because Mn has 7 (3d⁵ 4s²) valence electrons available and is in the middle of the series. The early (Sc, Ti) and late (Cu, Zn) members have fewer states.

Open this question →

How to practise

  1. Choose a d- and f-Block Elements question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Chemistry topics

Ideal and Non-Ideal SolutionsIdeal SolutionsNon-Ideal SolutionsReactions in Aqueous SolutionElectrochemistryElectrochemical SeriesSolutionsCoordination Compounds