Question Bank (Exam-Oriented)
MCQs + Fill in the Blanks + True/False + Assertion Reason + Very Short Answer
A. Multiple Choice Questions (MCQs)
1. Which of the following is a transition element?
A) Zn
B) Cd
C) Sc
D) Hg
Answer: C) Sc
2. The general electronic configuration of transition elements is:
A) ns²np⁶
B) (n−1)d¹–¹⁰ ns¹–²
C) ns²np¹–⁶
D) (n−2)f¹–¹⁴ns²
Answer: B
3. Which element is not considered a transition element?
A) Fe
B) Cu
C) Zn
D) Cr
Answer: C
4. The exceptional electronic configuration of chromium is:
A) 3d⁴4s²
B) 3d⁵4s¹
C) 3d³4s³
D) 3d⁶4s⁰
Answer: B
5. Copper has the electronic configuration:
A) 3d⁹4s²
B) 3d⁸4s²
C) 3d¹⁰4s¹
D) 3d⁷4s²
Answer: C
6. The highest oxidation state shown by manganese is:
A) +2
B) +4
C) +6
D) +7
Answer: D
7. The most common oxidation state of lanthanoids is:
A) +2
B) +3
C) +4
D) +5
Answer: B
8. Lanthanoid contraction occurs due to:
A) Poor shielding by 4f electrons
B) Large size of atoms
C) Complete filling of d-orbitals
D) High electronegativity
Answer: A
9. Which pair has nearly similar atomic sizes due to lanthanoid contraction?
A) Na and K
B) Zr and Hf
C) Cr and Mn
D) Fe and Co
Answer: B
10. Transition metal ions are often coloured because of:
A) High density
B) d-d transition
C) High melting point
D) Metallic bonding
Answer: B
11. Which ion is colourless?
A) Cu²⁺
B) Fe³⁺
C) Zn²⁺
D) Ni²⁺
Answer: C
12. The magnetic moment is calculated by:
A) μ = n(n+2)
B) μ = √n(n+2)
C) μ = n²
D) μ = √n
Answer: B
13. Which compound acts as a catalyst in the Contact process?
A) Fe
B) Ni
C) V₂O₅
D) MnO₂
Answer: C
14. Iron is used as a catalyst in:
A) Contact process
B) Haber process
C) Hydrogenation
D) Oxidation of alcohol
Answer: B
15. Tungsten carbide is an example of:
A) Alloy
B) Interstitial compound
C) Complex compound
D) Oxide
Answer: B
16. Potassium dichromate is:
A) Purple
B) Orange
C) Green
D) Blue
Answer: B
17. Potassium permanganate contains manganese in oxidation state:
A) +2
B) +4
C) +6
D) +7
Answer: D
18. Actinoids involve filling of:
A) 3d orbitals
B) 4f orbitals
C) 5f orbitals
D) 6d orbitals
Answer: C
19. All actinoids are:
A) Stable metals
B) Radioactive
C) Non-metals
D) Noble gases
Answer: B
20. Eu²⁺ is stable because it has:
A) 4f⁰ configuration
B) 4f⁷ configuration
C) 4f¹⁴ configuration
D) 5d¹ configuration
Answer: B
B. Fill in the Blanks
1. Transition elements belong to groups ______ to ______.
Answer: 3 to 12
2. The general electronic configuration of transition elements is ______.
Answer: (n−1)d¹–¹⁰ ns¹–²
3. Chromium has the configuration ______.
Answer: 3d⁵4s¹
4. Copper has the configuration ______.
Answer: 3d¹⁰4s¹
5. Zn²⁺ has ______ d-electrons.
Answer: 10
6. Lanthanoids involve filling of ______ orbitals.
Answer: 4f
7. Actinoids involve filling of ______ orbitals.
Answer: 5f
8. The most common oxidation state of lanthanoids is ______.
Answer: +3
9. Poor shielding by ______ electrons causes lanthanoid contraction.
Answer: 4f
10. The colour of transition metal ions is due to ______ transition.
Answer: d-d
11. The catalyst used in the Haber process is ______.
Answer: Iron
12. V₂O₅ is used in the ______ process.
Answer: Contact
13. KMnO₄ is a strong ______ agent.
Answer: Oxidising
14. K₂Cr₂O₇ contains chromium in oxidation state ______.
Answer: +6
15. Actinoids show more oxidation states because of the small energy difference between ______ orbitals.
Answer: 5f, 6d and 7s
C. True or False
1. Zn is a transition element.
Answer: False
2. Transition metals generally show variable oxidation states.
Answer: True
3. d⁰ and d¹⁰ ions are generally colourless.
Answer: True
4. Lanthanoid contraction is caused by poor shielding of 4f electrons.
Answer: True
5. All lanthanoids are radioactive.
Answer: False
6. All actinoids are radioactive.
Answer: True
7. Copper has a negative electrode potential.
Answer: False
8. Transition metals can form complex compounds.
Answer: True
9. Iron is used as catalyst in hydrogenation of oils.
Answer: False
(Nickel is used.)
10. KMnO₄ is purple in colour.
Answer: True
D. Assertion–Reason Questions
1.
Assertion: Transition elements show variable oxidation states.
Reason: Both ns and (n−1)d electrons participate in bonding.
A) Both A and R are true and R explains A
B) Both true but R does not explain A
C) A true, R false
D) A false, R true
Answer: A
2.
Assertion: Zn is not considered a transition element.
Reason: Zn has completely filled d-orbitals.
Answer: A
3.
Assertion: Lanthanoids are difficult to separate.
Reason: They have very similar atomic sizes.
Answer: A
4.
Assertion: Transition metal ions are coloured.
Reason: They show d-d electronic transitions.
Answer: A
5.
Assertion: Actinoids show more oxidation states than lanthanoids.
Reason: 5f, 6d and 7s orbitals have comparable energies.
Answer: A
E. Very Short Answer Questions
1. Why is Sc a transition element?
Answer:
Because Sc has an incomplete d-subshell (3d¹).
2. Why is Zn not a transition element?
Answer:
Because Zn and Zn²⁺ have completely filled d¹⁰ configuration.
3. Why do transition metals have high melting points?
Answer:
Due to strong metallic bonding involving d-electrons.
4. What causes colour in transition metal ions?
Answer:
d-d electronic transitions.
5. Why are lanthanoids called inner transition elements?
Answer:
Because electrons enter the inner 4f orbitals.
6. What is lanthanoid contraction?
Answer:
The gradual decrease in size of lanthanoid atoms and ions with increasing atomic number.
7. Name the catalyst used in the Contact process.
Answer:
Vanadium pentoxide (V₂O₅).
8. Name one interstitial compound.
Answer:
Tungsten carbide (WC).
9. Which ion is responsible for the purple colour of KMnO₄?
Answer:
MnO₄⁻ ion.
10. Which element shows the maximum oxidation states among the first transition series?
Answer:
Manganese.