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The D and F Block Class 12 Notes: CBSE Chemistry Chapter 4

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Class 12 Chemistry D and F block Elements Notes PDF Download

Vedantu offers Class 12 Chemistry Chapter 4: D and F Block Elements notes that simplify the complex properties and trends of these elements. These notes cover the d-block elements (transition metals) and f-block elements (lanthanoids and actinoids), explaining their electronic configurations, oxidation states, and industrial applications. Students can use these notes for better understanding and quick revision of important concepts before exams. Download the FREE PDF of these notes from Vedantu for a comprehensive study experience and thorough exam preparation.

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Class 12 Chapter 4 D and F Block Elements lets you quickly access and review the chapter content. For a comprehensive study experience, check out the Class 12 Chemistry Revision Notes FREE PDF here and refer to the CBSE Class 12 Chemistry syllabus for detailed coverage. Vedantu's notes offer a focused, student-friendly approach, setting them apart from other resources and providing you with the best tools for success.

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Access Class 12 Chemistry Chapter 4 The D and F Block Notes

1. Transition Elements (d-Block Elements)

  • Location in Periodic Table: Transition elements are positioned between the s-block and p -block elements, specifically between groups 2 and 13 of the Periodic Table.

  • Transition Series: There are three distinct transition series:

    • First Transition Series: Involves the filling of 3d-orbitals, ranging from Scandium (Z = 21) to Zinc (Z = 30).

    • Second Transition Series: Involves the filling of 4 d -orbitals, starting from Yttrium (Z = 39) to Cadmium (Z = 48).

    • Third Transition Series: Involves the filling of 5d-orbitals, beginning with Lanthanum (Z = 57). Following Lanthanum, the 14 elements known as Lanthanides fill the 4 f -orbitals. The series continues with elements from Hafnium (Z = 72) to Mercury (Z = 80).


2. Inner Transition Elements (f-Block Elements)

  • Definition: The f-block elements are referred to as inner transition elements.


3. General Characteristics of Transition Elements

  • Metallic Nature: All transition elements are metals, exhibiting high electrical and thermal conductivity.

  • Gradual Decrease in Electropositive Character: As we move across a period, transition elements gradually reduce electropositive character.

  • Physical Properties: Transition metals are generally hard, possess high densities, high enthalpies of atomisation, and high melting and boiling points, all due to strong metallic bonding. They also form alloys with other metals.

  • Melting Points: Melting points increase to a maximum and then decrease towards the end of the series. The strength of metallic bonds is linked to the number of half-filled d-orbitals.

  • Ionic Radii: The ionic radii decrease progressively across a given series, primarily due to the poor shielding effect of d-electrons.

  • Ionisation Energies: Transition elements have higher ionisation energies than s-block elements but lower than p -block elements. The ionisation energy generally increases across the series.

  • Oxidation States: Transition metals exhibit multiple oxidation states due to the involvement of (n s) and (n - 1) d-electrons in bonding.

  • Electropositive Nature: Most transition metals are sufficiently electropositive to react with mineral acids, releasing hydrogen gas.

  • Paramagnetism: Many transition elements and their compounds are paramagnetic.

  • Coloured Compounds: Transition metals often form coloured compounds in both solid state and aqueous solution, due to d-d transitions of electrons.

  • Complex Formation: Unlike s- and p-block elements, transition metals have a strong ability to form complexes, attributed to their small, highly charged ions and vacant (d) orbitals.

  • Catalytic Properties: Many transition metals and their compounds act as catalysts in various chemical reactions.

  • Interstitial Compounds: Transition metals are known to form a large number of interstitial compounds.

  • Alloy Formation: Transition metals form numerous alloys because their atoms can easily replace each other in the crystal lattice.

  • Oxides Nature: The oxides of transition metals in lower oxidation states are generally basic, while those in higher oxidation states are either amphoteric or acidic.


4. Lanthanides and Actinides (f-Block Elements)

Lanthanides:

  • General Electronic Configuration: $[\mathrm{Xe}] 4 \mathrm{f}^{1} \mathrm{I}^{14} 5 \mathrm{~d}^{0}-^{1} 6 \mathrm{~s}^{2} ) (n s)$ .

  • Physical Properties: Silvery-white, malleable, ductile metals with high melting points and densities.

  • Oxidation States: Primarily exhibit a +3 oxidation state, but some can also show $+2 (e.g., ( \mathrm{Eu}^{2+} ) ) \text{or} +4 (e.g., ( \mathrm{Ce}^{4+} ) )$ .

  • Colour: Many lanthanide ions are coloured due to electronic transitions between different 4 f -levels.

  • Magnetism: Most lanthanide ions are paramagnetic, except for those with no 4 f -electrons $(e.g., ( \mathrm{La}^{3+}, \mathrm{Ce}^{4+} ) ) \text{or a full 4 f -level} (e.g., ( \mathrm{Yb}^{2+}, \mathrm{Lu}^{3+} ) )+2 (e.g., ( \mathrm{Eu}^{2+} ) ) \text{or} +4 (e.g., ( \mathrm{Ce}^{4+} ))$ .

  • Reactivity: Lanthanides readily tarnish in air and react to form trioxides. The oxides and hydroxides of lanthanides are basic.

  • Ionic Nature: Lanthanide compounds are predominantly ionic.

  • Lanthanoid Contraction: A gradual decrease in atomic and ionic sizes across the lanthanide series, known as lanthanoid contraction.


Actinides:

  • Physical Properties: Silvery-white metals with moderately high melting points.

  • Ionic Size: The ionic size of actinides decreases gradually along the series.

  • Oxidation States: Actinides exhibit multiple oxidation states, with +4 being the most common. Some can also exhibit +6 oxidation states (e.g., uranium, neptunium, plutonium).

  • Radioactivity: Many actinides are radioactive, with elements beyond uranium being man-made.

  • Complex Formation: Actinides tend to form complexes more than lanthanides.


Class 12 Chemistry Chapters 4 Formulas and Concepts

  1. EAN = Number of valence electrons of metal ion−Charge on the metal ion + Number of ligands.

  2. Magnetic Moment (µ): The magnetic moment of a complex ion is given by the formula: µ = √n(n+2) BM

  3. Crystal Field Stabilization Energy (CFSE): CFSE = -0.4 × ▲o × n


Class 12 Chemistry Chapter 4 The D and F Block Notes Important Topics and Subtopics

S.No.

Topics

Subtopics

1

Introduction to D-Block Elements

General electronic configuration, Transition elements, Series of d-block elements

2

Properties of D-Block Elements

Coloured Variable oxidation states, Formation of coloured compounds, Magnetic properties, Complex formation

3

Catalytic Properties of Transition Metals

Role of d-block elements in catalysis

4

Intermetallic Compounds and Alloys

Types of alloys, Uses of transition metals in alloy formation

5

F-Block Elements: Lanthanoids

Electronic configuration, Oxidation states, Lanthanoid contraction, Chemical reactivity

6

F-Block Elements: Actinoids

Oxidation states, Actinoid contraction, Radioactive properties

7

Comparison Between Lanthanoids and Actinoids

Chemical and physical differences, Similarities, Uses

8

Applications of d and f Block Elements

Industrial applications, Biological importance



Importance of Revision Notes for Class 12 Chemistry Chapter 4

  • Summarises Key Points: Condenses important concepts for quick review.

  • Saves Time: Provides a fast way to revise before exams.

  • Highlights Essentials: Focuses on crucial topics and definitions.

  • Improves Memory: Helps in better retention of information.   

  • Enhances Exam Prep: Targets weak areas for more effective study.

  • Clarifies Concepts: Simplifies complex ideas for easier understanding.

  • Includes Visuals: Uses diagrams and charts for better grasp.

  • Boosts Confidence: Prepares students thoroughly for exams.


Tips for Learning the Class 12 Chemistry Chapter 4 

  1. Focus on core processes with illustrations and examples.

  2. Draw and label diagrams for clarity. 

  3. Create summaries of each process.

  4. Connect concepts to everyday examples.

  5. Solve past exam questions to test understanding.

  6. Explain concepts to others to reinforce learning.

  7. Revisit material frequently to retain information.

  8. Utilise platforms like Vedantu for additional support.


Conclusion

The Class 12 Chemistry Chapter 4: D and F Block Elements provides students with a comprehensive understanding of transition and inner transition elements. Through Vedantu's notes, students gain clarity on the trends and properties of these elements, their role in various industries, and their significance in everyday applications. Downloading the FREE PDF from Vedantu ensures easy access to well-structured revision notes, making exam preparation efficient and effective.


Related Study Materials for Class 12 Chemistry Chapter 4

S.No.

Important Study Material Links for Class 12 Chemistry Chapter 4

1.

Class 12 Chemistry The D and F Block Important Questions

2.

Class 12 Chemistry The D and F Block NCERT Solutions 

3.

Class 12 Chemistry The D and F Block Exemplar Solutions



Revision Notes Links for Class 12 Chemistry Revision Notes



Related Study Material Links for Class 12 Chemistry

FAQs on The D and F Block Class 12 Notes: CBSE Chemistry Chapter 4

1. What are the key concepts to focus on during quick revision of The D and F Block Elements in Class 12 Chemistry?

During quick revision, concentrate on the electronic configurations, oxidation states, general properties of transition and inner transition elements, trends in physical and chemical properties, lanthanoid contraction, and their industrial applications. Understanding these core areas ensures a strong foundation for exam questions based on CBSE Class 12 Chemistry Chapter 4.

2. How do the general properties of d-block elements help in connecting different topics during revision?

The general properties of d-block elements such as variable oxidation states, paramagnetism, alloy formation, complex compound formation, and catalytic behavior link to several chemistry chapters. Recognizing these patterns aids in synthesizing concepts across periodic trends, bonding, and coordination chemistry during your revision.

3. Why is the concept of lanthanoid contraction important when revising f-block elements?

Lanthanoid contraction refers to the gradual decrease in atomic and ionic size across the lanthanide series. This concept is essential because it explains why elements in the 5d transition series have similar sizes to their 4d counterparts, affecting chemical reactivity, separation techniques, and periodic trends.

4. What are the most effective strategies for summarizing Class 12 D and F Block revision notes?

  • Highlight key definitions and trends for transition and inner transition elements.
  • Use structured tables or diagrams for electronic configurations and oxidation states.
  • Create concept maps linking properties like color, magnetism, and catalytic activity.
  • Note down exceptions and comparative points.
  • Regularly test your understanding with self-explained summaries or practice questions.

5. How can students avoid common pitfalls while revising the D and F Block Elements chapter?

To avoid mistakes, students should clarify differences between transition and inner transition elements, not confuse oxidation states, carefully study color and magnetic properties, and avoid rote memorization without understanding trends. Frequent revision and cross-referencing with the official syllabus help prevent gaps in learning.

6. Which formulas are essential to memorize for The D and F Block Elements Class 12 Notes?

Important formulas include those for Effective Atomic Number (EAN), magnetic moment (μ = √n(n+2)), and Crystal Field Stabilization Energy (CFSE). Knowing these helps in solving numerical and concept-based problems as per CBSE guidelines.

7. What areas should be prioritized in last-minute revision for Class 12 Chemistry Chapter 4?

Prioritize oxidation states and trends, properties of transition and inner transition elements, differences between lanthanides and actinides, and key applications in industry and everyday life. Quick summaries and diagrams can further enhance retention during final revision rounds.

8. In what ways do transition metals differ from inner transition metals based on their revision notes?

  • Transition metals (d-block) have partially filled d-orbitals, show multiple oxidation states, form colored compounds, and act as catalysts.
  • Inner transition metals (f-block) have partially filled f-orbitals, show less variable oxidation states, display lanthanoid contraction, and often exhibit strong paramagnetism and radioactivity in actinides. Summarizing these differences aids comparative understanding during revision.

9. How does the structure of revision notes enhance memory retention for The D and F Block Elements?

Well-structured notes that summarize concepts in short paragraphs, organize information with headings, use visual aids like charts and diagrams, and highlight key terms promote easier recall and understanding. This enables faster and more effective revision aligned with the CBSE Class 12 Chemistry syllabus.

10. What conceptual link exists between the magnetic and colored nature of transition metal compounds, according to revision notes?

Both the magnetic and colored nature of transition metal compounds arise from unpaired d-electrons and electronic transitions between d-orbitals. This direct relationship is a critical connection point that helps students synthesize and retain related concepts efficiently during exam revision.