COMEDK UGET 2026 d and f Block Elements Practice Questions with Solutions

The d and f Block Elements chapter is one of the most scoring yet concept-sensitive areas for COMEDK UGET 2026 , and practicing d and f Block Elements Practice Questions with Solutions helps you convert theory into marks. As you prepare for this section, you must focus on understanding trends rather than memorising isolated facts. In COMEDK, questions from this chapter are usually direct, NCERT-based, and framed to test your conceptual clarity of periodic trends, oxidation states, and characteristic properties of transition and inner transition elements.

The important portions from d and f Block Elements that you must prioritise include electronic configuration of transition elements, variable oxidation states, trends in atomic and ionic radii, magnetic properties (paramagnetism and diamagnetism), colour of compounds, and catalytic behaviour. From the f-block, lanthanide contraction, oxidation states of lanthanides and actinides, and separation of lanthanides are particularly important. In previous years, COMEDK has repeatedly asked questions on spin-only magnetic moment formulas, comparison of oxidation states across a series, reasons behind colour and complex formation, and the effect of lanthanide contraction on atomic size and basicity.

Occasionally, questions integrate real-world scenarios such as explaining catalytic action in industrial processes or identifying compounds based on magnetic behavior or geometry making this chapter a frequently scoring area if well prepared. To prepare effectively for this chapter, you should first build strong conceptual clarity from NCERT, especially the tables and trend explanations, and then move to topic-wise practice questions with full solutions. You should practice numericals on magnetic moment calculation, revise standard oxidation states, and repeatedly analyse why certain metals show higher catalytic activity or form coloured ions. While solving previous-year COMEDK-level questions, you must note recurring areas such as lanthanide contraction and oxidation state stability, as these are favourite testing zones.

COMEDK UGET 2026 'd and f' Block Elements Important Topics

The chapter on 'd and f' Block Elements in COMEDK UGET 2026 Chemistry syllabus covers several subtopics, including the occurrence and characteristics of transition metals, general trends in the properties of first-row transition metals—such as metallic character, ionization enthalpy, and oxidation states, among others. It is important to note that the COMEDK UGET exam will feature important questions based on these topics. Therefore, you must focus on these areas. Below is the list of COMEDK UGET 2026 'd and f' Block Elements subtopics for exam preparation.

Also Check - Do or Die Chapters for COMEDK UGET 2026 Chemistry

COMEDK UGET 2026 'd and f' Block Elements Expected Weightage

As an aspirant examinee, you must be aware of the weightage and the total number of questions that the 'd and f' Block Elements topic will carry. Understanding this will help you prepare effectively. The table below provides a summary of the expected weightage of the COMEDK UGET 'd and f' Block Elements, along with the expected number of topics.

Important Portions from d and f Block Elements & Study Strategy

Candidates can check the below table to know the important portions and how they can study.

COMEDK UGET 2026 'd and f' Block Elements Practice Questions with Solutions

Regularly practicing COMEDK UGET 'd and f' Block Elements sample questions can greatly improve your exam preparation. By solving COMEDK 'd and f' Block Elements practice questions with solutions, you can get acquainted with potential exam questions, confirm correct answers, and grasp step-by-step solutions. Below are some key COMEDK UGET 2026 'd and f' Block Elements practice questions, carefully curated by experts from past exam papers.

Q1. Identify the correct statement from the following:

a) The green manganate ion shows diamagnetic nature but the permanganate ion exhibits paramagnetic nature.

b) Interstitial compounds of transition metals have lower melting points than that of pure transition metals and their compounds are chemically reactive

c) Cerium is a lanthanoid metal which exists in a stable oxidation state of +4, besides exhibiting an oxidation state of +3

d) Cr (VI) is more stable than W (VI) and hence acts as a good oxidising agent

Correct answer: c) Cerium is a lanthanoid metal which exists in a stable oxidation state of +4, besides exhibiting an oxidation state of +3

Solution: Each of the given statements needs to be examined carefully to identify the correct one. Let's analyze them one by one:

Option A: The green manganate ion shows diamagnetic nature, but the permanganate ion exhibits paramagnetic nature.

This statement is not correct because both the manganate ion (MnO ^2- ₄ ) and the permanganate ion (MnO ^- ₄ ) are paramagnetic in nature, as both contain unpaired electrons in their d-orbitals.

Option B: Interstitial compounds of transition metals have lower melting points than that of pure transition metals and their compounds are chemically reactive.

This statement is also not correct. Interstitial compounds typically have higher melting points compared to their pure metals due to the presence of small atoms (like hydrogen, carbon, or nitrogen) in the interstices of the metal lattice structure, which enhances the metallic bonding. Additionally, they are generally less reactive than their constituent metals.

Option C: Cerium is a lanthanoid metal which exists in a stable oxidation state of +4, besides exhibiting an oxidation state of +3.

This statement is correct. Cerium (Ce) indeed has two common oxidation states: +3 and +4. The +3 oxidation state is more common for lanthanoids, but cerium is unique in that it can exist stably in the +4 oxidation state as well.

Option D: Cr (VI) is more stable than W (VI) and hence acts as a good oxidising agent.

This statement is not correct. In fact, W(VI) is generally more stable than Cr(VI), Chromium (VI) compounds are strong oxidizing agents, indicating they are less stable and readily reduced.

Therefore, the correct statement is:

Option C: Cerium is a lanthanoid metal which exists in a stable oxidation state of +4, besides exhibiting an oxidation state of +3.

Q2. The correct order of increasing melting point is:

a) CR < Ti < V < Mn

b) Mn < TI < V < Cr

c) Ti < V < Cr < Mn

d) V < Ti < Mn < Cr

Correct answer: b) Mn < TI < V < Cr

Solution: We can compare the approximate melting points in (in ℃) of the given elements:

Manganese (Mn) ~ 1246℃

Titanium (Ti) ~ 1668℃

Chromium (Cr) ~ 1907℃

Vanadium (V) ~ 1910℃

Thus, when we order them from lowest to highest, we have:

Mn (1246℃) < Ti (1668℃) < Cr (1907℃) < V (1910℃)

However, note that the melting points of chromium and vanadium are extremely close (differing by only about 3℃); in many texts and competitive exam questions the order is given using one of these two as the highest. Among the provided options, only Option B begins with manganese as the lowest and titanium following it. Option B gives:

Mn < TI < V < Cr

This is the answer most commonly accepted in such questions, even though some sources might slightly swap the last two due to the close values.

Thus, the answer is Option B.

Q3. In 3d-transmission series, which one has the least melting point?

a) V

b) Zn

c) Mn

d) Cu

Correct answer: b) Zn

Solution: The melting point of d-block elements is due to the presence of unpaired electrons in the last d-orbital or s-orbital. So, the element which has all the electrons in pairs will have the least melting point.

[Ar] 3d ³ 4s ² has 3 unpaired electrons.

[Ar] 3d ¹⁰ 4s ² has zero unpaired electron.

[Ar] 3d ⁵ 4s ² has five unpaired electrons.

[Ar] 3d ¹⁰ 4s ¹ has one unpaired electron.

Therefore, zinc has least melting point.

Q4. Formation of coloured solution is possible, when metal ion in the compound contains

a) paired electrons

b) unpaired electrons

c) Ione pair of electrons

d) None of the above

Correct answer: b) unpaired electrons

Solution: Formation of coloured solution is possible, when metal ion in the compound contains unpaired electrons due to transition of electrons in excited state.

Q5. Which of the following forms a colourless solution in aqueous medium?

a) Ti ³⁺

b) Sc ³⁺

c) V ³⁺

d) Cr ³⁺

Correct answer: b) Sc ³⁺

Solution: The electronic configuration of Sc is

1s ² 2s ² 2p ⁶ 3s ² 3p ⁶ 3d ¹ 4s ²

Electronic configuration of Sc ³⁺ is 1s ² 2s ² 2p ⁶ 3s ² 3p ⁶

So, Sc ³⁺ is colourless due to the absence of unpaired electrons in d-orbital.

Previous Year d & f Block Elements Topic-wise Question Mapping

Check the below table to know the trend of topics that are asked every year in COMEDK exam.

10-Day Micro-Revision Plan for d & f Block Elements

Follow this routine.

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