d- and f-Block Elements Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which compound is used in the preparation of KMnO4?

Pyrolusite ore (MnO2) is fused with KOH and oxidized to form KMnO4.

FeCr2O4
CuFeS2
ZnS
MnO2
4

Which transition metal has the highest melting point in the 3d series?

Tungsten (W) has the highest melting point among transition metals (3422°C).

Cr
W
Fe
Ni
2

What is the effect of lanthanoid contraction on the atomic sizes of post-lanthanoid elements?

Lanthanoid contraction causes similar atomic sizes of 4d and 5d transition elements.

Increases their sizes
No effect
Makes 4d and 5d elements similar in size
Decreases their densities
3

What is the electronic configuration of Cr (Z = 24) in its ground state?

Cr has an anomalous configuration due to the stability of half-filled d orbitals: [Ar] 3d5 4s1.

[Ar] 3d4 4s2
[Ar] 3d5 4s1
[Ar] 3d6
[Ar] 3d3 4s2 4p1
1

Which of the following is a characteristic property of f-block elements?

Lanthanoid contraction is the gradual decrease in atomic/ionic radii across the lanthanoid series.

Variable oxidation states
Lanthanoid contraction
High volatility
Formation of colored ions
1

Which lanthanoid exhibits +4 oxidation state due to its noble gas-like configuration?

Cerium (Ce) shows +4 state to achieve stable 4f0 configuration (like Xenon).

La
Ce
Gd
Lu
1

Which of the following transition metal compounds is diamagnetic?

ZnSO4 contains Zn2+ with 3d10 configuration (all electrons paired).

FeSO4
CuSO4
ZnSO4
NiSO4
1

Which of the following lanthanoids shows +4 oxidation state?

Cerium (Ce) exhibits +4 oxidation state due to the stability of empty 4f orbitals (4f0).

La
Ce
Gd
Lu
1

Which of the following oxidation states is most common for lanthanoids?

+3 is the predominant oxidation state for lanthanoids due to the stability of Ln3+ ions.

+2
+3
+4
+5
1

What is the primary reason for the high melting points of transition metals?

Strong metallic bonding due to involvement of d-electrons in bonding.

Small atomic size
Involvement of d-electrons in bonding
Low ionization energy
Presence of f-electrons
4

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