D AND F BLOCK ELEMENTS - 20 NEET MCQs

D and F Block Elements - NEET Level MCQs

1. The element with the highest melting point among transition metals is:
   a) Fe
   b) W
   c) Cu
   d) Cr


2. Which of the following ions is colorless?
   a) Ti³⁺
   b) V³⁺
   c) Zn²⁺
   d) Cr³⁺


3. Which of the following shows the highest oxidation state?
   a) Mn
   b) Fe
   c) Cr
   d) Co


4. Lanthanide contraction is responsible for:
   a) Similar atomic sizes of Zr and Hf
   b) Increase in ionic radii
   c) Increase in oxidation state
   d) Formation of colored compounds


5. The general electronic configuration of d-block elements is:
   a) (n−1)d^1–10ns^0–2
   b) (n−2)d^1–10ns²
   c) ns²np⁶
   d) (n−1)d¹⁰ns²


6. Which of the following transition metals does not form colored compounds?
   a) Cu
   b) Zn
   c) Fe
   d) Co


7. The magnetic moment of Mn²⁺ is:
   a) 1.73 BM
   b) 5.92 BM
   c) 3.87 BM
   d) 2.83 BM


8. Which oxidation state is most stable for Fe?
   a) +1
   b) +2
   c) +3
   d) +6


9. Which of the following has the highest ionic radius?
   a) Fe²⁺
   b) Fe³⁺
   c) Mn²⁺
   d) Cr³⁺


10. Which of the following pairs shows similar atomic radii due to lanthanide contraction?
    a) Zr and Nb
    b) Zr and Hf
    c) Ti and Zr
    d) Mo and W


11. Actinides show greater range of oxidation states because:
    a) 5f, 6d and 7s levels are close in energy
    b) 4f orbitals are completely filled
    c) 5f orbitals are inner orbitals
    d) They are non-metals


12. The color of KMnO₄ is due to:
    a) Charge transfer from O to Mn
    b) d–d transition
    c) f–f transition
    d) π→π* transition


13. The element showing +7 oxidation state is:
    a) Mn
    b) Fe
    c) Co
    d) Cr


14. The most common oxidation state of lanthanoids is:
    a) +1
    b) +2
    c) +3
    d) +4


15. The actinide which is used as a nuclear fuel is:
    a) Thorium
    b) Uranium
    c) Neptunium
    d) Curium


16. Which lanthanoid shows +4 oxidation state most commonly?
    a) Ce
    b) Eu
    c) Gd
    d) Tb


17. The decreasing order of ionic radii among the following is:
    a) Fe²⁺ > Mn²⁺ > Cr²⁺
    b) Mn²⁺ > Fe²⁺ > Co²⁺
    c) Cr²⁺ > Mn²⁺ > Fe²⁺
    d) Fe²⁺ > Co²⁺ > Ni²⁺


18. The highest oxidation state of uranium is:
    a) +4
    b) +5
    c) +6
    d) +7


19. Transition metals form complex compounds due to:
    a) Small size
    b) High nuclear charge and availability of vacant d orbitals
    c) Low ionization enthalpy
    d) Large size

Answers & Solutions:

1-b) Tungsten has the highest melting point among transition metals.
2-c) Zn²⁺ has a completely filled d¹⁰ configuration → colorless.
3-a) Mn shows +7 oxidation state (Mn₂O₇).
4-a) Lanthanide contraction causes similar sizes of Zr and Hf.
5-a) (n−1)d¹–¹⁰ ns⁰–² is correct for d-block.
6-b) Zn²⁺ (d¹⁰) → no color.
7-b) Mn²⁺ has 5 unpaired electrons → 5.92 BM.
8-b) Fe²⁺ is more stable than Fe³⁺ in aqueous solution.
9-c) Mn²⁺ has the highest ionic radius.
10-b) Zr and Hf show almost same radii due to lanthanide contraction.
11-a) Actinides have close 5f, 6d, 7s energy levels → variable oxidation states.
12-a) KMnO₄ color due to charge transfer (O → Mn).
13-a) Mn shows +7 state (KMnO₄).
14-c) +3 is the most stable oxidation state of lanthanoids.
15-b) Uranium is used as nuclear fuel (U-235).
16-a) Ce⁴⁺ (CeO₂) is most common +4 lanthanoid.
17-b) Mn²⁺ > Fe²⁺ > Co²⁺ (decreasing ionic radius with increasing nuclear charge).
18-c) Uranium shows +6 in UO₂²⁺.
19-b) Due to small size, high charge and vacant d orbitals, transition metals form complexes.
20-b) High charge density and vacant orbitals favor complex formation.