COMEDK 2025 Afternoon Shift | d and f Block Elements Question 15 | Chemistry

$$\mathrm{A}=\mathrm{Cr}^{2+}(\mathrm{Z}=24) \mathrm{B}=\mathrm{Cu}^{2+}(\mathrm{Z}=29) \quad \mathrm{C}=\mathrm{Ni}^{2+}(\mathrm{Z}=28) \mathrm{D}=\mathrm{Fe}^{3+}(\mathrm{Z}=26)$$

$\mathrm{B}<\mathrm{C}<\mathrm{A}<\mathrm{D}$

$\mathrm{D}<\mathrm{C}<\mathrm{A}<\mathrm{B}$

$\mathrm{B}<\mathrm{C}<\mathrm{D}<\mathrm{A}$

$\mathrm{C}<\mathrm{B}<\mathrm{D}<\mathrm{A}$

COMEDK 2025 Afternoon Shift

MCQ (Single Correct Answer)

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Arrange the following ions in the decreasing order of covalent double bonds formed by the transition metal with oxygen.

A. $=$ chromate $\mathrm{B}=$ permanganate $\mathrm{C}=$ dichromate

$\mathrm{A}>\mathrm{B}>\mathrm{C}$

$\mathrm{B}>\mathrm{C}>\mathrm{A}$

$\mathrm{B}>\mathrm{A}>\mathrm{C}$

$\mathrm{C}>\mathrm{B}>\mathrm{A}$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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Match the metals in Column II with their characteristic properties given in Column I.

	Properties		Metals
A.	Lanthanoid with low value of $3^{\text {rd }}$ ionisation enthalpy.	P	V
B.	f-Block element with electronic configuration $[R n] 6 d^2 7 s^2$	Q	Gd
C.	3 d -series metal whose $\mathrm{M}^{3+}{ }_{(\mathrm{aq})}$ is colourless.	R	Th
D.	3d-series metal with highest $\Delta \mathrm{H}_{\text {(atomisation) }}$	S	Sc

$\mathrm{A}=\mathrm{Q} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P}$

$\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{Q} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P}$

$\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{Q} \quad \mathrm{C}=\mathrm{P} \quad \mathrm{D}=\mathrm{S}$

$\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P}$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

-0

Choose the correct statement.

Ionic compounds of $\mathrm{Sc}^{3+}$ and $\mathrm{Cu}^{+}$are coloured because of $\mathrm{d}-\mathrm{d}$ electronic transitions

The order in which the paramagnetic nature of the 4 cations $\mathrm{Cr}^{2+}, \mathrm{Mn}^{2+}, \mathrm{V}^{2+}$ and $\mathrm{Fe}^{2+}$ vary is $\mathrm{V}^{2+}<\mathrm{Cr}^{2+}=\mathrm{Mn}^{2+}<\mathrm{Fe}^{2+}$

As the oxidation number of the transition element increases, the ionic nature decreases and the oxides show acidic nature predominantly

The metal Cobalt has the electronic configuration $[\mathrm{Ar}] 3 \mathrm{~d}^5$ in the +3 oxidation state

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Some Basic Concepts of Chemistry Atomic Structure States of Matter Thermodynamics Chemical Equilibrium Ionic Equilibrium Liquid Solution Redox Reactions Surface Chemistry Solid State Electrochemistry Chemical Kinetics Nuclear Chemistry

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Metallurgy Periodic Table and Periodicity Hydrogen and It's Compounds p-Block Elements Environmental Chemistry Coordination Compounds d and f Block Elements s-Block Elements Chemical Bonding and Molecular Structure

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