d- and f-Block Elements

34 solved questions from Class 12 Chemistry, each with the full working. Tap any question to see the step-by-step solution.

• 1 What is the primary chemical reaction or bonding mechanism highlighted in 'd- and f-Block Elements' (Class 12)? medium MCQ Reaction Mechanism & Bonding
• 2 What factor affects the rate or equilibrium constant of reactions in 'd- and f-Block Elements'? medium MCQ Chemical Kinetics & Factors
• 3 Which functional group or IUPAC nomenclature rule applies to compounds in 'd- and f-Block Elements'? medium MCQ IUPAC Nomenclature & Structure
• 4 What is the major product obtained in the characteristic reaction of 'd- and f-Block Elements'? medium MCQ Reaction Products & Selectivity
• 5 Which oxidation state is most commonly exhibited by the lanthanide elements in their aqueous compounds? easy MCQ 1 mark common oxidation state of lanthanides
• 6 Write the ground‑state electron configuration for the element having the configuration [Xe]4f^145d^16s^2. Identify the element and state whether it belongs to the d‑block or f‑block of the periodic table. medium 2 marks identifying element from electron configuration
• 7 A transition metal ion is d^6 in a high‑spin octahedral complex. The octahedral crystal‑field splitting energy Δ_o is 18,000 cm^-1 and the electron‑pairing energy P is 12,000 cm^-1. Calculate the crystal‑field stabilization energy (CFSE) for the high‑spin and low‑spin possibilities and decide which spin state is favoured. medium 3 marks CFSE calculation for d^6 octahedral complexes
• 8 Write the ground‑state electron configuration of yttrium (Y) and indicate whether it belongs to the d‑block or f‑block of the periodic table. medium 2 marks Electronic configuration and block identification
• 9 Which of the following lanthanide ions has the smallest ionic radius? easy MCQ 1 mark Lanthanide contraction and ionic radii
• 10 Explain why the +2 oxidation state is relatively more stable for the heavier lanthanides (such as Yb and Lu) compared to the lighter lanthanides. Include in your answer the role of 4f‑electron shielding and ionisation energies. hard 5 marks Oxidation states of lanthanides and 4f shielding effect
• 11 For the octahedral complex [Fe(H₂O)₆]²⁺ (high‑spin), calculate the number of unpaired electrons and the spin‑only magnetic moment (in Bohr magnetons). medium 3 marks Crystal field theory and magnetic moment of transition metal complexes
• 12 The octahedral complex [Co(NH_3)_6]^3+ is a d^6 system. Given the octahedral crystal‑field splitting energy Δ_o=22,000 cm^-1 and the electron‑pairing energy P=15,000 cm^-1, calculate the crystal‑field stabilization energy (CFSE) for both the high‑spin and low‑spin configurations and indicate which configuration is favoured. hard 3 marks CFSE calculation and spin‑state prediction for octahedral $d^{6}$ complexes
• 13 Write the ground‑state electron configuration of the lanthanide element terbium (Tb, Z = 65) and state the oxidation state that is most commonly exhibited by lanthanide ions in aqueous solution. medium 2 marks Electron configuration and common oxidation state of lanthanides
• 14 Which of the following elements is placed in the d‑block of the periodic table? easy MCQ 1 mark Identification of d‑block element
• 15 Explain the phenomenon of lanthanide contraction. In your answer, discuss (i) the cause of the contraction, (ii) how it influences the ionic radii across the lanthanide series, and (iii) the effect of this contraction on the chemical properties of the subsequent 4d and 5d transition‑series elements. hard 5 marks Lanthanide contraction and its periodic‑trend consequences
• 16 For the octahedral complex [Fe(CN)₆]⁴⁻ (which has a d⁶ configuration), given the octahedral crystal‑field splitting energy Δₒ = 20 000 cm⁻¹ and the electron‑pairing energy P = 10 000 cm⁻¹, calculate the crystal‑field stabilization energy (CFSE) for both the high‑spin and low‑spin configurations and decide which spin state is favoured. medium 3 marks CFSE calculation for octahedral complexes
• 17 Which of the following elements is placed in the d‑block of the periodic table? easy MCQ 1 mark Periodic table blocks
• 18 Explain the phenomenon of lanthanide contraction and discuss in detail how it influences (i) the ionic radii across the lanthanide series, (ii) the chemical properties of the lanthanides, and (iii) the periodic trends of the 4d and 5d transition‑series elements, particularly in terms of atomic radius, coordination numbers, and bonding characteristics. hard 5 marks Lanthanide contraction and its effects
• 19 Write the ground‑state electron configuration of the element scandium (Z = 21) and state whether it belongs to the d‑block or f‑block. medium 2 marks Electron configuration of transition metals
• 20 For the octahedral complex [CoF_6]^3- (Co^3+, d^6), the crystal‑field splitting energy Δ_o is 18,000 cm^-1 and the electron‑pairing energy P is 12,000 cm^-1. Calculate the crystal‑field stabilization energy (CFSE) for both the high‑spin and low‑spin configurations and determine which spin state is favoured. medium 4 marks Crystal‑field stabilization energy calculation
• 21 Which element belongs to the f‑block of the periodic table? easy MCQ 2 marks Identification of f‑block elements
• 22 For the octahedral complex [Cr(NH_3)_6]^3+ (Cr^3+, d^3), the octahedral crystal‑field splitting energy is Δ_o = 15,000;cm^-1 and the electron‑pairing energy is P = 8,000;cm^-1. Calculate the crystal‑field stabilization energy (CFSE) for both the high‑spin and low‑spin configurations and determine which spin state is favoured. medium 3 marks CFSE calculation for d3 complex
• 23 Determine the number of unpaired electrons and the spin‑only magnetic moment (in Bohr magnetons) for the octahedral complex [Mn(H_2O)_6]^2+ (Mn^2+, d^5). medium 2 marks Magnetic properties of high‑spin complexes
• 24 Which of the following elements is an f‑block element of the periodic table? easy MCQ 2 marks Identification of f‑block elements
• 25 Consider the octahedral complex [Fe(CN)_6]^4- (Fe^2+, d^6). Given the octahedral crystal‑field splitting energy Δ_o = 21,000;cm^-1 and the electron‑pairing energy P = 12,000;cm^-1, calculate the crystal‑field stabilization energy (CFSE) for the high‑spin and low‑spin configurations. Which spin state is favoured? hard 4 marks CFSE and spin state selection
• 26 Which of the following elements is an f‑block element of the periodic table? easy MCQ 1 mark Identification of f‑block element
• 27 Explain the phenomenon of lanthanide contraction. In your answer discuss (i) the cause of the contraction, (ii) how it influences the ionic radii across the lanthanide series, and (iii) the effect of this contraction on the chemical properties and periodic trends of the subsequent 4d and 5d transition‑series elements, especially regarding atomic radius, coordination numbers and bonding characteristics. hard 4 marks Lanthanide contraction and its consequences
• 28 Which of the following elements is placed in the f‑block of the periodic table? easy MCQ 1 mark Identification of f‑block elements
• 29 The oxidation state most commonly exhibited by lanthanide ions in aqueous solutions is: medium MCQ 1 mark Common oxidation state of lanthanides
• 30 An octahedral complex of a metal ion has a d^4 configuration. The crystal‑field splitting energy is Δ_o=18,000 cm^-1 and the pairing energy is P=11,000 cm^-1. Calculate the crystal‑field stabilization energy (CFSE) for the low‑spin configuration and decide whether the low‑spin or high‑spin state is favoured. medium 2 marks CFSE calculation and spin‑state preference
• 31 Explain the phenomenon of lanthanide contraction, describing (i) the cause of the contraction and (ii) how it influences the ionic radii across the lanthanide series. medium 3 marks Lanthanide contraction effect on radii
• 32 Which of the following elements is placed in the d‑block of the periodic table? easy MCQ 1 mark Block classification of elements
• 33 Explain the phenomenon of lanthanide contraction and its impact on the periodic trends of the subsequent 4d and 5d transition‑series elements, especially regarding atomic radius, coordination numbers and bonding characteristics. hard 5 marks Lanthanide contraction effect on transition metals
• 34 Which of the following elements is a d‑block element? A) Ytterbium (Yb) B) Yttrium (Y) C) Lutetium (Lu) D) Thorium (Th) easy MCQ 1 mark Identify d‑block element