ROUTERA


Chapter 8 The d and f Block Elements

Class 12th Chemistry Chapter MCQs


1. Which of the following is a characteristic of d-block elements?

a) They have completely filled d-orbitals.
b) They form only ionic compounds.
c) They are good conductors of electricity.
d) They have similar properties to the s-block elements.
Answer: c) They are good conductors of electricity.
Explanation: d-block elements are good conductors of electricity due to the presence of free electrons in their d-orbitals.


2. Which of the following elements exhibits the highest oxidation state?

a) Mn
b) Fe
c) Cr
d) Cu
Answer: a) Mn
Explanation: Manganese exhibits the highest oxidation state of +7 in compounds such as potassium permanganate (KMnO₄).


3. Which of the following is not a property of transition elements?

a) Formation of colored compounds
b) Formation of complex compounds
c) High melting and boiling points
d) High electronegativity
Answer: d) High electronegativity
Explanation: Transition elements have low electronegativity compared to s-block elements.


4. Which of the following elements forms a compound with the formula [Ni(CO)₄]?

a) Nickel
b) Cobalt
c) Copper
d) Iron
Answer: a) Nickel
Explanation: [Ni(CO)₄] is a nickel carbonyl complex where nickel is in the zero oxidation state.


5. Which of the following compounds is an example of an interstitial compound?

a) NaCl
b) Fe₄C
c) AgNO₃
d) CuSO₄
Answer: b) Fe₄C
Explanation: Fe₄C is an interstitial compound where small carbon atoms occupy the interstitial spaces in the iron lattice.


6. The color of [Cu(H₂O)₆]²⁺ in aqueous solution is due to

a) Charge transfer transition
b) d-d transition
c) Excitation of electrons in the s-orbital
d) Ligand to metal charge transfer
Answer: b) d-d transition
Explanation: The blue color of [Cu(H₂O)₆]²⁺ is due to d-d transition of electrons in the d-orbitals of Cu²⁺.


7. Which of the following is the highest oxidation state of an element in the d-block?

a) +2
b) +3
c) +6
d) +7
Answer: d) +7
Explanation: Manganese exhibits the highest oxidation state of +7 in KMnO₄.


8. Which of the following elements shows the maximum number of oxidation states?

a) Manganese
b) Chromium
c) Iron
d) Copper
Answer: a) Manganese
Explanation: Manganese can exhibit oxidation states from +2 to +7, making it the element with the maximum number of oxidation states.


9. Which of the following transition elements shows the +2 oxidation state most commonly?

a) Fe
b) Cu
c) Cr
d) Mn
Answer: b) Cu
Explanation: Copper most commonly exists in the +2 oxidation state as Cu²⁺ in compounds like copper sulfate (CuSO₄).


10. Which of the following ions has the most stable electronic configuration?

a) Mn²⁺
b) Fe²⁺
c) Co²⁺
d) Cu²⁺
Answer: d) Cu²⁺
Explanation: Cu²⁺ has a stable electronic configuration of [Ar] 3d⁹, which is relatively stable due to the pairing of electrons in the d-orbital.


11. Which of the following is a characteristic of the lanthanide series?

a) They show only one oxidation state.
b) They are all radioactive.
c) They are found in nature in their pure form.
d) They are all f-block elements.
Answer: d) They are all f-block elements.
Explanation: The lanthanides are f-block elements characterized by filling of the 4f orbitals.


12. Which of the following is the correct electronic configuration of a transition metal in the +3 oxidation state?

a) [Ar] 3d⁶
b) [Ar] 3d⁵
c) [Ar] 3d⁸
d) [Ar] 4s⁰ 3d⁶
Answer: a) [Ar] 3d⁶
Explanation: In the +3 oxidation state, a transition metal typically loses three electrons, resulting in the electronic configuration [Ar] 3d⁶.


13. Which of the following elements is used in the preparation of magnets?

a) Chromium
b) Cobalt
c) Copper
d) Iron
Answer: b) Cobalt
Explanation: Cobalt is widely used in the preparation of magnets due to its magnetic properties.


14. Which of the following compounds is formed when transition metals react with oxygen?

a) Oxides
b) Peroxides
c) Superoxides
d) All of the above
Answer: d) All of the above
Explanation: Transition metals can form oxides, peroxides, or superoxides depending on their oxidation state and the nature of the compound.


15. Which of the following elements is known to form a +2 oxidation state more easily than other oxidation states?

a) Iron
b) Copper
c) Chromium
d) Manganese
Answer: b) Copper
Explanation: Copper easily forms the +2 oxidation state due to its stable d⁹ electronic configuration.


16. Which of the following is the formula for potassium dichromate?

a) K₂CrO₄
b) K₂Cr₂O₇
c) KCrO₄
d) KCr₂O₇
Answer: b) K₂Cr₂O₇
Explanation: Potassium dichromate has the formula K₂Cr₂O₇, where chromium is in the +6 oxidation state.


17. Which of the following elements is used in the manufacture of stainless steel?

a) Manganese
b) Chromium
c) Cobalt
d) Iron
Answer: b) Chromium
Explanation: Chromium is a key component in stainless steel, providing resistance to corrosion.


18. Which of the following transition metals is used in catalytic converters?

a) Platinum
b) Iron
c) Copper
d) Nickel
Answer: a) Platinum
Explanation: Platinum is widely used in catalytic converters to reduce harmful emissions in vehicles.


19. The color of potassium permanganate (KMnO₄) is due to

a) Charge transfer transitions
b) d-d transition
c) Ligand to metal charge transfer
d) Excitation of electrons in the s-orbital
Answer: a) Charge transfer transitions
Explanation: The purple color of KMnO₄ is due to charge transfer transitions from the oxygen to the manganese atom.


20. Which of the following is the common oxidation state of iron in its compounds?

a) +3
b) +2
c) +6
d) +5
Answer: b) +2
Explanation: Iron commonly exhibits +2 oxidation state in compounds such as FeSO₄.


21. Which of the following is true for the lanthanide contraction?

a) It leads to an increase in atomic size.
b) It leads to a decrease in ionization enthalpy.
c) It leads to a decrease in atomic size.
d) It leads to an increase in the electronegativity of lanthanides.
Answer: c) It leads to a decrease in atomic size.
Explanation: The lanthanide contraction refers to the gradual decrease in atomic and ionic sizes from La to Lu due to poor shielding by the f-electrons.


22. Which of the following transition metal oxides is amphoteric?

a) Cr₂O₃
b) Fe₂O₃
c) MnO₂
d) NiO
Answer: a) Cr₂O₃
Explanation: Cr₂O₃ is amphoteric and reacts with both acids and bases.


23. Which of the following is the most stable oxidation state of copper in its compounds?

a) +1
b) +2
c) +3
d) +4
Answer: b) +2
Explanation: Copper most commonly exists in the +2 oxidation state as Cu²⁺.


24. Which of the following lanthanides is used in the preparation of high-temperature superconductors?

a) Cerium
b) Neodymium
c) Samarium
d) Yttrium
Answer: d) Yttrium
Explanation: Yttrium is used in the preparation of high-temperature superconductors.


25. Which of the following is the correct electronic configuration of Cr³⁺?

a) [Ar] 3d⁶
b) [Ar] 3d⁵
c) [Ar] 3d⁴
d) [Ar] 3d⁸
Answer: b) [Ar] 3d⁵
Explanation: Cr³⁺ has the electronic configuration [Ar] 3d⁵, as it loses three electrons.


26. Which of the following is not a property of transition metals?

a) Formation of colored complexes
b) High melting and boiling points
c) Ability to form complex compounds
d) High electronegativity
Answer: d) High electronegativity
Explanation: Transition metals have lower electronegativity compared to other non-metals.


27. Which of the following is used in the preparation of catalysts?

a) Silver
b) Gold
c) Platinum
d) Lead
Answer: c) Platinum
Explanation: Platinum is used as a catalyst in several industrial processes, such as catalytic converters in automobiles.


28. Which of the following ions has a d⁴ configuration?

a) Mn²⁺
b) Fe²⁺
c) Cr²⁺
d) Co²⁺
Answer: a) Mn²⁺
Explanation: Mn²⁺ has the electronic configuration 3d⁵ 4s² and loses two electrons to attain a d⁴ configuration.


29. Which of the following elements is a transition metal?

a) Calcium
b) Silicon
c) Manganese
d) Oxygen
Answer: c) Manganese
Explanation: Manganese is a transition metal, whereas calcium, silicon, and oxygen are not.


30. Which of the following is true for d-block elements?

a) They have only one oxidation state.
b) They form only ionic bonds.
c) They form colored compounds.
d) They are non-metals.
Answer: c) They form colored compounds.
Explanation: D-block elements often form colored compounds due to electronic transitions within their d-orbitals.


31. Which of the following is the formula for chromium trioxide?

a) CrO₃
b) Cr₂O₃
c) CrO₄
d) CrO₂
Answer: a) CrO₃
Explanation: Chromium trioxide has the formula CrO₃, commonly used as an oxidizing agent.


32. Which of the following transition elements is found in the +3 oxidation state most frequently?

a) Chromium
b) Manganese
c) Iron
d) Copper
Answer: b) Manganese
Explanation: Manganese frequently forms the +3 oxidation state in its compounds.


33. Which of the following is true about the magnetic properties of transition elements?

a) They are generally diamagnetic.
b) They are generally paramagnetic.
c) They are generally ferromagnetic.
d) They are generally anti-magnetic.
Answer: b) They are generally paramagnetic.
Explanation: Due to the presence of unpaired electrons, transition metals are generally paramagnetic.


34. Which of the following ions has a 3d⁷ configuration?

a) Fe³⁺
b) Mn²⁺
c) Co²⁺
d) Ni²⁺
Answer: d) Ni²⁺
Explanation: Ni²⁺ has the electronic configuration 3d⁸, but upon ionization it gives a 3d⁷ configuration.


35. Which of the following properties is characteristic of the f-block elements?

a) They form only ionic compounds.
b) They have very high melting points.
c) They are typically soft and ductile.
d) They have a large number of oxidation states.
Answer: b) They have very high melting points.
Explanation: F-block elements, especially the lanthanides, have high melting points due to the strong metallic bonds in their structures.


36. Which of the following is used in the preparation of high-strength magnets?

a) Neodymium
b) Scandium
c) Thulium
d) Europium
Answer: a) Neodymium
Explanation: Neodymium is used to prepare high-strength magnets used in various technological applications.


37. Which of the following elements shows the highest oxidation state in its compounds?

a) Iron
b) Chromium
c) Manganese
d) Copper
Answer: c) Manganese
Explanation: Manganese shows the highest oxidation state of +7 in KMnO₄.


38. Which of the following is a property of copper (Cu)?

a) It is highly reactive with oxygen.
b) It shows only one oxidation state, +1.
c) It is a poor conductor of electricity.
d) It is used extensively in electrical wiring.
Answer: d) It is used extensively in electrical wiring.
Explanation: Copper is widely used in electrical wiring due to its excellent conductivity.


39. The d-block elements are also called

a) Transition elements
b) Noble gases
c) Halogens
d) Alkali metals
Answer: a) Transition elements
Explanation: d-block elements are called transition elements because they lie between s-block and p-block elements.


40. Which of the following elements shows the +3 oxidation state in all of its compounds?

a) Iron
b) Chromium
c) Manganese
d) Aluminum
Answer: d) Aluminum
Explanation: Aluminum always shows the +3 oxidation state in its compounds.


41. Which of the following transition metals shows the maximum number of oxidation states?

a) Chromium
b) Manganese
c) Copper
d) Zinc
Answer: b) Manganese
Explanation: Manganese can show oxidation states from +2 to +7, the maximum for any element in the d-block.


42. Which of the following is an example of a complex compound formed by a transition metal?

a) NaCl
b) [Cu(NH₃)₄]²⁺
c) Fe₂O₃
d) Na₂SO₄
Answer: b) [Cu(NH₃)₄]²⁺
Explanation: [Cu(NH₃)₄]²⁺ is a complex ion formed by copper, demonstrating the typical behavior of transition metals in forming complex compounds.


43. Which of the following ions is isoelectronic with Argon (Ar)?

a) Fe²⁺
b) Cr³⁺
c) Mn²⁺
d) Co²⁺
Answer: b) Cr³⁺
Explanation: Cr³⁺ has the electronic configuration of [Ar], making it isoelectronic with argon.


44. Which of the following is the correct electronic configuration of the transition element manganese (Mn)?

a) [Ar] 3d⁵ 4s²
b) [Ar] 3d⁴ 4s²
c) [Ar] 3d⁶ 4s²
d) [Ne] 3s² 3p⁶ 3d⁵ 4s¹
Answer: a) [Ar] 3d⁵ 4s²
Explanation: The electronic configuration of Mn is [Ar] 3d⁵ 4s².


45. Which of the following elements is known for the formation of colored complexes?

a) Sodium
b) Copper
c) Calcium
d) Magnesium
Answer: b) Copper
Explanation: Copper forms various colored complexes, such as [Cu(H₂O)₆]²⁺.


46. Which of the following is not a feature of transition metals?

a) Ability to form complex compounds
b) Formation of colored compounds
c) High electronegativity
d) Ability to form multiple oxidation states
Answer: c) High electronegativity
Explanation: Transition metals have lower electronegativity than non-metals.


47. Which of the following is used in the extraction of aluminum from bauxite?

a) Sodium hydroxide
b) Sodium chloride
c) Potassium hydroxide
d) Iron oxide
Answer: a) Sodium hydroxide
Explanation: Sodium hydroxide is used in the Bayer process to extract aluminum from bauxite.


48. Which of the following compounds contains a metal in its highest oxidation state?

a) K₂Cr₂O₇
b) FeCl₃
c) CuSO₄
d) ZnCl₂
Answer: a) K₂Cr₂O₇
Explanation: In potassium dichromate (K₂Cr₂O₇), chromium has an oxidation state of +6, which is the highest oxidation state of chromium.


49. Which of the following is true about transition metals?

a) They have a low melting point
b) They are typically highly reactive
c) They form highly stable and reactive oxides
d) They exhibit high electrical conductivity
Answer: d) They exhibit high electrical conductivity
Explanation: Transition metals are good conductors of electricity due to the presence of free electrons in their d-orbitals.


50. Which of the following compounds is used as a catalyst in the hydrogenation of vegetable oils?

a) Ni
b) Pt
c) Pd
d) Ag
Answer: a) Ni
Explanation: Nickel (Ni) is commonly used as a catalyst in the hydrogenation of vegetable oils.