Class 12 Chemistry Chapter 4 The d-and f-Block Elements MCQs Updated 2024 – MyNoteswala

Q.1: The element which shows only +3 oxidation state among the following is:
(a) Iron
(b) Copper
(c) Cobalt
(d) Chromium

Answer: (c) Cobalt
Explanation: Cobalt predominantly shows the +3 oxidation state.

Q.2: The electronic configuration of Fe²⁺ ion is:
(a) [Ar] 3d⁶
(b) [Ar] 3d⁷
(c) [Ar] 3d⁵
(d) [Ar] 3d⁸

Answer: (a) [Ar] 3d6
Explanation: Iron in the +2 oxidation state loses two electrons from the 4s orbital.

Q.3: Which one of the following is a common oxidation state for all actinoids?
(a) +3
(b) +4
(c) +5
(d) +6

Answer: (b) +4 Explanation: Actinoids commonly exhibit the +4 oxidation state.

Q.4: The element which does not form a stable +2 oxidation state is:
(a) Zinc
(b) Cadmium
(c) Mercury
(d) Cobalt

Answer: (d) Cobalt
Explanation: Cobalt predominantly forms stable +2 and +3 oxidation states.

Q.5: Which of the following is a metal?
(a) Ce
(b) Mn
(c) Cr
(d) La

Answer: (b) Mn
Explanation: Manganese (Mn) is a transition metal.

Q.6: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.7: Which of the following is not a transition element?
(a) Zinc
(b) Scandium
(c) Cobalt
(d) Aluminium

Answer: (d) Aluminium
Explanation: Aluminium does not belong to the d-block.

Q.8: The electronic configuration of Cu+ ion is:
(a) [Ar] 3d¹⁰
(b) [Ar] 3d⁹
(c) [Ar] 3d⁸
(d) [Ar] 3d⁷

Answer: (b) [Ar] 3d⁹
Explanation: Copper in the +1 oxidation state loses one electron from the 4s orbital.

Q.9: The element which does not form a stable +3 oxidation state is:
(a) Chromium
(b) Iron
(c) Manganese
(d) Cobalt

Answer: (a) Chromium
Explanation: Chromium forms stable +2 and +6 oxidation states, but not +3.

Q.10: Which one of the following is a lanthanoid?
(a) Eu
(b) Ni
(c) Co
(d) Zn

Answer: (a) Eu
Explanation: Europium (Eu) is a lanthanoid element.

Q.11: The element which shows maximum number of oxidation states is:
(a) Iron
(b) Manganese
(c) Cobalt
(d) Chromium

Answer: (b) Manganese
Explanation: Manganese exhibits a wide range of oxidation states from +2 to +7.

Q.12: The element which shows a variable oxidation state of +2 and +3 is:
(a) Manganese
(b) Vanadium
(c) Iron
(d) Cobalt

Answer: (c) Iron
Explanation: Iron commonly exhibits both +2 and +3 oxidation states.

Q.13: Which of the following is a common oxidation state for all actinoids?
(a) +2
(b) +3
(c) +4
(d) +5

Answer: (c) +4 Explanation: Actinoids commonly exhibit the +4 oxidation state.

Q.14: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.15: Which of the following elements is not a transition element?
(a) Zinc
(b) Scandium
(c) Cobalt
(d) Aluminium

Answer: (d) Aluminium Explanation: Aluminium does not belong to the d-block.

Q.16: The element which does not form a stable +3 oxidation state is:
(a) Chromium
(b) Iron
(c) Manganese
(d) Cobalt

Answer: (a) Chromium Explanation: Chromium forms stable +2 and +6 oxidation states, but not +3.

Q.17: Which one of the following is a lanthanoid?
(a) Eu
(b) Ni
(c) Co
(d) Zn

Answer: (a) Eu Explanation: Europium (Eu) is a lanthanoid element.

Q.18: The element which shows a variable oxidation state of +2 and +3 is:
(a) Manganese
(b) Vanadium
(c) Iron
(d) Cobalt

Answer: (c) Iron
Explanation: Iron commonly exhibits both +2 and +3 oxidation states.

Q.19: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.20: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.21: The electronic configuration of Mn²⁺ ion is:
(a) [Ar] 3d⁵
(b) [Ar] 3d⁶
(c) [Ar] 3d⁷
(d) [Ar] 3d⁸

Answer: (a) [Ar] 3d⁵
Explanation: Manganese in the +2 oxidation state loses two electrons from the 4s and 3d orbitals, resulting in an electronic configuration of [Ar] 3d⁵.

Q.22: The element which does not form a stable +2 oxidation state is:
(a) Zinc
(b) Cadmium
(c) Mercury
(d) Cobalt

Answer: (d) Cobalt
Explanation: Cobalt predominantly forms stable +2 and +3 oxidation states.

Q.23: Which of the following is a metal?
(a) Ce
(b) Mn
(c) Cr
(d) La

Answer: (b) Mn
Explanation: Manganese (Mn) is a transition metal.

Q.24: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.25: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.26: The electronic configuration of Cu⁺ ion is:
(a) [Ar] 3d¹⁰
(b) [Ar] 3d⁹
(c) [Ar] 3d⁸
(d) [Ar] 3d⁷

Answer: (b) [Ar] 3d⁹
Explanation: Copper in the +1 oxidation state loses one electron from the 4s orbital, resulting in an electronic configuration of [Ar] 3d⁹.

Q.27: The element which shows a variable oxidation state of +2 and +3 is:
(a) Manganese
(b) Vanadium
(c) Iron
(d) Cobalt

Answer: (c) Iron
Explanation: Iron commonly exhibits both +2 and +3 oxidation states.

Q.28: Which of the following elements is not a transition element?
(a) Zinc
(b) Scandium
(c) Cobalt
(d) Aluminium

Answer: (d) Aluminium
Explanation: Aluminium does not belong to the d-block.

Q.29: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.30: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.31: The electronic configuration of Mn²⁺ ion is:
(a) [Ar] 3d⁵
(b) [Ar] 3d⁶
(c) [Ar] 3d⁷
(d) [Ar] 3d⁸

Answer: (a) [Ar] 3d⁵
Explanation: Manganese in the +2 oxidation state loses two electrons from the 4s and 3d orbitals, resulting in an electronic configuration of [Ar] 3d⁵.

Q.32: The element which does not form a stable +2 oxidation state is:
(a) Zinc
(b) Cadmium
(c) Mercury
(d) Cobalt

Answer: (d) Cobalt
Explanation: Cobalt predominantly forms stable +2 and +3 oxidation states.

Q.33: Which of the following is a metal?
(a) Ce
(b) Mn
(c) Cr
(d) La

Answer: (b) Mn
Explanation: Manganese (Mn) is a transition metal.

Q.34: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.35: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.36: The electronic configuration of Cu⁺ ion is:
(a) [Ar] 3d¹⁰
(b) [Ar] 3d⁹
(c) [Ar] 3d⁸
(d) [Ar] 3d⁷

Answer: (b) [Ar] 3d^9
Explanation: Copper in the +1 oxidation state loses one electron from the 4s orbital, resulting in an electronic configuration of [Ar] 3d^9.

Q.37: The element which shows a variable oxidation state of +2 and +3 is:
(a) Manganese
(b) Vanadium
(c) Iron
(d) Cobalt

Answer: (c) Iron
Explanation: Iron commonly exhibits both +2 and +3 oxidation states.

Q.38: Which of the following elements is not a transition element?
(a) Zinc
(b) Scandium
(c) Cobalt
(d) Aluminium

Answer: (d) Aluminium
Explanation: Aluminium does not belong to the d-block.

Q.39: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.40: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.41: The electronic configuration of Mn²⁺ ion is:
(a) [Ar] 3d⁵
(b) [Ar] 3d⁶
(c) [Ar] 3d⁷
(d) [Ar] 3d⁸

Answer: (a) [Ar] 3d⁵
Explanation: Manganese in the +2 oxidation state loses two electrons from the 4s and 3d orbitals, resulting in an electronic configuration of [Ar] 3d⁵.

Q.42: The element which does not form a stable +2 oxidation state is:
(a) Zinc
(b) Cadmium
(c) Mercury
(d) Cobalt

Answer: (d) Cobalt
Explanation: Cobalt predominantly forms stable +2 and +3 oxidation states.

Q.43: Which of the following is a metal?
(a) Ce
(b) Mn
(c) Cr
(d) La

Answer: (b) Mn
Explanation: Manganese (Mn) is a transition metal.

Q.44: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.45: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

Q.46: The electronic configuration of Cu⁺ ion is:
(a) [Ar] 3d¹⁰
(b) [Ar] 3d⁹
(c) [Ar] 3d⁸
(d) [Ar] 3d⁷

Answer: (b) [Ar] 3d⁹
Explanation: Copper in the +1 oxidation state loses one electron from the 4s orbital, resulting in an electronic configuration of [Ar] 3d⁹.

Q.47: The element which shows a variable oxidation state of +2 and +3 is:
(a) Manganese
(b) Vanadium
(c) Iron
(d) Cobalt

Answer: (c) Iron
Explanation: Iron commonly exhibits both +2 and +3 oxidation states.

Q.48: Which of the following elements is not a transition element?
(a) Zinc
(b) Scandium
(c) Cobalt
(d) Aluminium

Answer: (d) Aluminium
Explanation: Aluminium does not belong to the d-block.

Q.49: The element which forms a coloured compound in +3 oxidation state is:
(a) Scandium
(b) Vanadium
(c) Manganese
(d) Chromium

Answer: (d) Chromium
Explanation: Chromium compounds in +3 oxidation state are often coloured.

Q.50: The element which forms only +2 oxidation state among the following is:
(a) Manganese
(b) Iron
(c) Chromium
(d) Vanadium

Answer: (d) Vanadium
Explanation: Vanadium predominantly forms the +2 oxidation state in its compounds.

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