Class 12 D and F Block Important Questions 2026 | CBSE Chemistry High Weightage Topics
Table of Contents
Introduction
The D and F Block Elements chapter in Class 12 Chemistry is one of the most important and scoring chapters in the CBSE board exam.
Questions from this chapter are repeated every year in short, long, and case-based formats.
If students prepare smartly, they can easily score full marks in this unit.
High Weightage Topics in D and F Block (CBSE Trend)
| Topic | Importance Level |
|---|---|
| Transition Elements Properties | ⭐⭐⭐⭐⭐ |
| Lanthanides and Actinides | ⭐⭐⭐⭐⭐ |
| Electronic Configuration | ⭐⭐⭐⭐ |
| Oxidation States | ⭐⭐⭐⭐⭐ |
| Complex Formation | ⭐⭐⭐⭐ |
| Magnetic Properties | ⭐⭐⭐⭐ |
These topics are guaranteed exam questions.
Most Important D Block Questions for CBSE 2026
1. General Properties of Transition Elements
Expected Questions
-
Why are transition elements called d-block elements?
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Explain variable oxidation states in transition metals.
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Why do transition metals show paramagnetism?
-
Explain catalytic properties of transition elements.
2. Electronic Configuration
Repeated Questions
-
Write the electronic configuration of Cr and Cu and explain exceptions.
-
Explain stability of half-filled and fully filled orbitals.
3. Oxidation States (Very Important)
| Element | Common Oxidation States |
|---|---|
| Mn | +2, +4, +7 |
| Fe | +2, +3 |
| Cu | +1, +2 |
| Cr | +2, +3, +6 |
Repeated Questions
-
Why do transition elements show variable oxidation states?
-
Compare oxidation states of first, second, and third transition series.
4. Magnetic Properties
Expected Questions
-
Define paramagnetism and diamagnetism.
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Explain spin-only magnetic moment formula.
-
Why are transition metals paramagnetic?
5. Complex Formation
Frequently Asked Questions
-
What are coordination compounds?
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Why do transition metals form complexes?
-
Explain ligands and coordination number.
Most Important F Block Questions (Lanthanides & Actinides)
6. Lanthanides
Repeated Questions
-
Define lanthanide contraction.
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Causes and consequences of lanthanide contraction.
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Oxidation states of lanthanides.
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Applications of lanthanides.
7. Actinides
Expected Questions
-
Electronic configuration of actinides.
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Why do actinides show radioactivity?
-
Compare lanthanides and actinides.
Difference Between D Block and F Block (Very Important Table)
| Feature | D Block | F Block |
|---|---|---|
| Orbital | d-orbital | f-orbital |
| Series | 3 transition series | Lanthanides & Actinides |
| Oxidation States | Variable | Mostly +3 |
| Magnetic Nature | Paramagnetic | Strongly paramagnetic |
| Radioactivity | No | Actinides are radioactive |
Most Expected Long Answer Questions (5 Marks)
-
Explain general characteristics of transition elements.
-
Describe lanthanide contraction and its effects.
-
Compare lanthanides and actinides.
-
Explain oxidation states and magnetic properties of transition metals.
-
Write short notes on complex formation and catalytic properties.
These questions appear every year in different formats.
Last Minute Revision Tips for D and F Block
| Time Left | What to Revise |
|---|---|
| 1 Day | Oxidation states + Lanthanide contraction |
| 3 Hours | Magnetic properties + Complexes |
| 1 Hour | Definitions and exceptions |
| 30 Minutes | Important tables and differences |
Tips to Score High Marks in Chemistry
-
Write definitions clearly
-
Use tables and diagrams
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Highlight keywords like oxidation state, contraction, paramagnetism
-
Practice previous year questions
-
Learn exceptions (Cr, Cu) properly
Chemistry is concept-based, so clarity is important.
Conclusion
The D and F Block Elements chapter is a guaranteed scoring unit in CBSE Class 12 Chemistry.
By focusing on oxidation states, lanthanide contraction, magnetic properties, and complex formation, students can easily pass and score high marks.
Smart revision of repeated questions and tables can help you score 80–100% marks in this chapter.
Click Here to Know More about CBSE Class 12 Chemistry Syllabus 2025–26 | Units, Chapters & Marks Distribution Details: https://dekhocampus.com/news/cbse-class-12-chemistry-syllabus-2025-26
FAQs (Frequently Asked Questions)
Lanthanide contraction, oxidation states, magnetic properties, and complex formation.
Yes, it is one of the most scoring chapters with repeated questions every year.
Usually 3–8 marks every year depending on the paper pattern.
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