Class 12 P Block D Block and F Block Notes

Class 12 P Block D Block and F Block Notes | Important Questions & NCERT Chemistry

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In Class 12 Chemistry, the chapters P Block Elements, D Block Elements, and F Block Elements are extremely important for CBSE board exams, NEET, JEE, and other competitive exams. Students often find these chapters difficult because they involve periodic trends, properties, reactions, compounds, and exceptions.

This blog provides Class 12 P Block D Block and F Block Notes in a simple, exam-oriented, and student-friendly way. All important concepts, trends, reactions, and frequently asked questions are explained clearly so that students can revise quickly and score high marks.

Class 12 P Block D Block and F Block Notes
Class 12 P Block D Block and F Block Notes

 

Table of Contents

Class 12 P Block D Block and F Block Notes | Important Questions & NCERT Chemistry

What are P Block Elements?

P block elements are those elements in which the last electron enters the p-subshell. These elements are present in groups 13 to 18 of the periodic table.

General Electronic Configuration:
👉 ns² np¹–⁶

Groups included in P Block

  • Group 13 – Boron family
  • Group 14 – Carbon family
  • Group 15 – Nitrogen family
  • Group 16 – Oxygen family
  • Group 17 – Halogens
  • Group 18 – Noble gases

Important Trends in P Block Elements

1. Atomic Size

  • Increases down the group
  • Decreases from left to right in a period

2. Ionization Energy

  • Decreases down the group
  • Noble gases have very high ionization energy

3. Electronegativity

  • Decreases down the group
  • Halogens have high electronegativity

4. Oxidation States

  • Variable oxidation states are common
  • Inert pair effect observed in heavier elements

Group 13: Boron Family

Elements: B, Al, Ga, In, Tl

Key Properties

  • Boron is a non-metal, others are metals
  • +3 oxidation state common
  • +1 oxidation state stable in Tl (inert pair effect)

Important Compounds

  • Boric acid (H₃BO₃) – weak acid
  • AlCl₃ – Lewis acid
  • Diborane (B₂H₆) – electron deficient compound

Group 14: Carbon Family

Elements: C, Si, Ge, Sn, Pb

Key Points

  • Carbon shows catenation
  • Oxidation states: +4 and +2
  • Lead shows +2 oxidation state due to inert pair effect

Important Compounds

  • CO₂ – acidic oxide
  • SiO₂ – giant covalent structure
  • SnCl₂ & SnCl₄

Group 15: Nitrogen Family

Elements: N, P, As, Sb, Bi

Important Features

  • Oxidation states: –3 to +5
  • Nitrogen shows maximum covalency
  • NH₃ is a strong base

Important Compounds

  • Ammonia (NH₃)
  • Nitric acid (HNO₃)
  • Phosphine (PH₃)

Group 16: Oxygen Family

Elements: O, S, Se, Te, Po

Important Points

  • Oxygen is highly electronegative
  • Shows –2 oxidation state
  • Sulphur shows variable oxidation states

Important Compounds

  • SO₂, SO₃
  • H₂SO₄ (very important)

Group 17: Halogens

Elements: F, Cl, Br, I

Key Properties

  • Highly electronegative
  • Strong oxidizing agents
  • Exist as diatomic molecules

Important Compounds

  • HCl, HBr, HI
  • Bleaching powder
  • Chlorine water

Group 18: Noble Gases

Elements: He, Ne, Ar, Kr, Xe

Key Points

  • Chemically inert
  • Monoatomic gases
  • Xe forms compounds like XeF₂, XeF₄

D BLOCK ELEMENTS (Transition Elements Notes)

Class 12 P Block D Block and F Block Notes
Class 12 P Block D Block and F Block Notes

What are D Block Elements?

D block elements are those elements in which the last electron enters the d-orbital. These are known as transition elements.

General Electronic Configuration:
👉 (n–1)d¹–¹⁰ ns⁰–²

Characteristics of D Block Elements

1. Variable Oxidation States

Example:

  • Fe → +2, +3
  • Mn → +2 to +7

2. Formation of Coloured Compounds

Due to d–d electronic transitions

3. Magnetic Properties

  • Paramagnetic behavior due to unpaired electrons

4. Catalytic Properties

  • Fe → Haber process
  • V₂O₅ → Contact process

Important Transition Metals

Iron (Fe)

  • Used in construction
  • Important compounds: FeCl₃, FeSO₄

Copper (Cu)

  • Good conductor
  • CuSO₄ (Blue vitriol)

Zinc (Zn)

  • Used for galvanization
  • ZnSO₄ important salt

F BLOCK ELEMENTS (Inner Transition Elements)

Class 12 P Block D Block and F Block Notes
Class 12 P Block D Block and F Block Notes

What are F Block Elements?

F block elements are those in which the last electron enters the f-orbital.

Types of F Block Elements

  1. Lanthanides (4f series)
  2. Actinides (5f series)

Lanthanides

Properties

  • Also called rare earth elements
  • Oxidation state mainly +3
  • Show lanthanide contraction

Uses

  • Glass polishing
  • Magnets
  • Catalysts

Actinides

Properties

  • Mostly radioactive
  • Show multiple oxidation states
  • More reactive than lanthanides

Important Elements

  • Uranium (U)
  • Thorium (Th)
  • Plutonium (Pu)

Differences Between Lanthanides and Actinides

Property Lanthanides Actinides
Radioactivity Mostly non-radioactive Radioactive
Oxidation State +3 +3 to +6
Reactivity Less More

Important Exam-Oriented Points

  • Inert pair effect increases down p-block
  • Colour in d-block due to unpaired electrons
  • Lanthanide contraction affects atomic size
  • Transition metals form complexes easily

Why These Notes Are Important for Students

  • Written as per NCERT syllabus
  • Helpful for board + competitive exams
  • Easy language & clear concepts
  • Covers frequently asked questions
  • Best for last-minute revision

Conclusion-Class 12 P Block D Block and F Block Notes

The chapters Class 12 P Block D Block and F Block Elements are scoring if prepared properly. Understanding trends, properties, reactions, and exceptions is the key to success. These detailed notes help students build strong concepts and revise effectively.

If you want to score high in Class 12 Chemistry, make sure you revise these chapters multiple times with proper examples and questions.

Class 12 P Block D Block and F Block Important Questions (Repeated & Exam-Oriented)

🔴 P BLOCK ELEMENTS – Important Questions

Very Short Answer Questions (1 Mark)

  1. What is meant by inert pair effect?
  2. Why is boron a non-metal while others in group 13 are metals?
  3. Why is NH₃ basic in nature?
  4. Why does fluorine show only –1 oxidation state?
  5. Why noble gases are chemically inert?

Short Answer Questions (2–3 Marks)

  1. Explain the trend of oxidation states in group 15 elements.
  2. Why is AlCl₃ a Lewis acid?
  3. Write two uses of halogens.
  4. Explain why oxygen shows negative oxidation state.
  5. Why is lead(II) compounds more stable than lead(IV)?

Long Answer Questions (5 Marks – Repeated)

  1. Explain inert pair effect with suitable examples.
  2. Discuss the anomalous behavior of nitrogen.
  3. Describe the manufacture, properties and uses of ammonia.
  4. Explain the properties of halogens and their compounds.
  5. Write a detailed note on noble gas compounds of xenon.

🔵 D BLOCK ELEMENTS – Important Questions

Very Short Answer (1 Mark)

  1. What are transition elements?
  2. Why do transition metals show variable oxidation states?
  3. Name a transition metal used as a catalyst.
  4. What causes colour in transition metal ions?
  5. Which element shows maximum oxidation states?

Short Answer (2–3 Marks)

  1. Why are transition metals paramagnetic?
  2. Explain the formation of coloured compounds in d-block elements.
  3. Why do transition metals form complex compounds?
  4. Write two differences between Zn and other transition metals.
  5. Explain the catalytic activity of transition metals.

Long Answer Questions (5 Marks – Very Important)

  1. Explain the general characteristics of transition elements.
  2. Discuss the oxidation states of 3d series elements.
  3. Write a detailed note on magnetic properties of transition metals.
  4. Explain the preparation, properties and uses of potassium dichromate.
  5. Write short notes on Fe, Cu and Zn.

🟢 F BLOCK ELEMENTS – Important Questions

Very Short Answer (1 Mark)

  1. What are inner transition elements?
  2. Name the two series of f-block elements.
  3. What is lanthanide contraction?
  4. Which actinide is used as nuclear fuel?
  5. Why actinides are radioactive?

Short Answer (2–3 Marks)

  1. Explain lanthanide contraction.
  2. Why do actinides show more oxidation states than lanthanides?
  3. Write two uses of lanthanides.
  4. Compare lanthanides and actinides.
  5. Why actinides are more reactive?

Long Answer Questions (5 Marks – Highly Repeated)

  1. Explain lanthanide contraction and its consequences.
  2. Discuss the general properties of lanthanides.
  3. Explain the general characteristics of actinides.
  4. Write differences between lanthanides and actinides.
  5. Write a detailed note on uses of f-block elements.

⭐ Most Repeated HOT Questions (Board + NEET)

Class 12 P Block D Block and F Block Notes
Class 12 P Block D Block and F Block Notes
  • Inert pair effect
  • Lanthanide contraction
  • Coloured compounds of transition metals
  • Variable oxidation states
  • Differences: P block vs D block, Lanthanides vs Actinides
  • Xenon compounds
  • Magnetic properties of d-block

📌 Exam Tip for Students

👉 In boards, 5-mark questions mostly come from:

  • Inert pair effect
  • Transition metal properties
  • Lanthanide contraction
  • Xenon compounds

👉 For NEET/JEE, focus on:

  • Trends
  • Oxidation states
  • Exceptions
  • Reason-based questions

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