The d- and f-Block Elements Chapter-Wise Test 3

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following transition metals has the lowest melting point?

Zinc (Zn) has a low melting point (420°C) due to completely filled d-orbitals (3d10), reducing metallic bonding strength.

Fe
Zn
Cr
Ni
2

What is the product when K2Cr2O7 reacts with KI in acidic medium?

Cr2O72- oxidizes I- to I2 and gets reduced to Cr3+ (green).

CrO42- and I2
Cr3+ and I2
Cr2+ and I-
CrO2 and IO3-
2

What is the oxidation state of Mn in KMnO4?

KMnO4 has Mn in +7 oxidation state (highest oxidation state for Mn).

+5
+6
+7
+4
3

Which of the following is NOT a characteristic property of transition elements?

Transition elements typically have high melting points due to strong metallic bonding involving d-electrons, so low melting points is not a characteristic property.

Formation of colored ions
Variable oxidation states
Low melting points
Catalytic activity
3

Which of the following is NOT a property of transition metals?

Transition metals typically have high melting points due to strong metallic bonding.

Variable oxidation states
Formation of colored ions
Low melting points
Catalytic activity
3

Which lanthanoid commonly exhibits both +2 and +3 oxidation states due to extra stability of half-filled f-orbitals?

Europium (Eu) shows +2 oxidation state due to the stability of half-filled 4f7 configuration, along with the common +3 state.

Eu
Ce
Gd
Lu
1

Which of the following ions has the highest magnetic moment?

Mn2+ has 5 unpaired electrons (3d5), giving the highest magnetic moment (5.92 BM).

Fe2+ (3d6)
Ni2+ (3d8)
Mn2+ (3d5)
Co2+ (3d7)
3

Which of the following is NOT a use of transition metal compounds?

Transition metal compounds are not used as food preservatives.

Catalysts
Pigments
Food preservatives
Alloy formation
3

Which of the following oxidation states is exhibited by all lanthanoids?

All lanthanoids show the +3 oxidation state, though some may also exhibit +2 or +4 states.

+2
+3
+4
+5
2

Which of the following ions is paramagnetic?

Co2+ has 3 unpaired electrons (3d7 configuration), making it paramagnetic.

Zn2+
Cu+
Co2+
Sc3+
3

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