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d and f Block NCERT Solutions cover the d-block of the periodic table, which includes the elements of groups 3-12, and the f-block, which includes elements in which 4 f and 5 f orbitals are progressively filled. To refer to the d-and f-blocks, the names transition metals and inner transition metals are used, respectively.
The transition metals in the NCERT Solutions for Class 12 Chemistry Chapter 4 include precious metals like gold, silver, and platinum. It also includes industrially important metals like copper, iron, and titanium.
This chapter explores the occurrence, electronic configuration, and general characteristics of transition elements with a focus on trends in the properties of 3d (first row) of the transition metals. The NCERT solutions are created by experts, and students can rely on these for their exam preparation. It will help them to score high in their CBSE Board exams and other competitive exams like NEET and JEE Main exams.
To get the comprehensive Class 12 Chemistry Notes, which include the topic-wise PDF and solved exercises for quick revision, the students must explore here.
- Key Highlights of d and f block elements Class 12 NCERT Solutions
- Class 12 Chemistry Chapter 4 d and f block Elements: Topics Covered, Weightage
- NCERT Chemistry Class 12 The d and f Block Elements: Important Formulae
- NCERT Solutions Class 12 Chapter 4 d and f-block elements PDF : Download PDF For Free
- Class 12 Chapter 4 The d- and f- block Elements NCERTSolutions: Intext Questions ons
- Benefit of using NCERT Solutions for Class 12 Chemistry Chapter 4
- NCERT Chemistry Chapter 4 The d and f Block Elements – FAQs
Key Highlights of d and f block elements Class 12 NCERT Solutions
Here is a quick summary of the d and f block elements Class 12 Chemistry:
- In the periodic table, the d-block occupies the large middle section. It consists of Groups 3-12.
- Outside the bottom of the periodic table, the f-block is placed, in this part 4f and 5f orbitals are progressively filled.
- Three series of transition elements corresponding to the filling of 3d, 4d, and 5d orbitals are well recognized.
- The transition elements have metallic properties, including ductility, high tensile strength, thermal, malleability, electrical conductivity, and metallic character.
- With increasing atomic number, successive ionisation enthalpies do not increase as steeply as in the main group elements.
- The transition elements vary a lot in their chemical behavior. Also, it reacts with various non-metals like nitrogen, oxygen, halogens, and sulphur to form binary compounds.
- The applications of the d- and f- block elements are found in catalysts, steels, organic syntheses, and complexes.
Related Links
| NCERT Notes for Class 11 & 12 | Class 12 Chemistry NCERT Solutions | NCERT Solutions Class 11 and 12 for Maths, Physics, Chemistry |
Class 12 Chemistry Chapter 4 d and f block Elements: Topics Covered, Weightage
While practicing from the d and f block NCERT solutions, focus on trends in properties like oxidation states, atomic radii, ionization enthalpy, catalytic properties of d-block elements, properties and uses of important compounds like K2Cr2O7 and KMnO4. See below the topics covered in the NCERT Solutions d and f block elements class 12:
| Exercise | Topics Covered |
|---|---|
| 4.1 | Position in the Periodic Table |
| 4.2 | Electronic Configurations of the d-Block Elements |
| 4.3 | General Properties of the Transition Elements (d-Block) |
| 4.4 | Some Important Compounds of Transition Elements |
| 4.5 | The Lanthanoids |
| 4.6 | The Actinoids |
| 4.7 | Some Applications of d- and f- Block Elements |
d and f block elements class 12 Chemistry Chapter 4 Weightage in NEET and JEE Main exam
| Exam | Number of Questions | Weightage |
|---|---|---|
| NEET | 2 questions | 6% |
| JEE Main | few questions | 2.8% |
NCERT Chemistry Class 12 The d and f Block Elements: Important Formulae
Important Concepts and Formulae of Class 12 d and f block elements
- General electronic configuration of d-block elements:
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Cu and Cr are exceptions
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Magnetic moment ( ) depends on unpaired electrons:
where n = number of unpaired electrons.
- f-Block Elements (Inner Transition Elements)
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Lanthanides (4f-series): General Configuration,
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Actinides (5f-series): General Configuration,
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- Uses of Lanthanides:
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Alloys (Mischmetal used in aircraft engines).
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Glass polishing & phosphors in TV screens.
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- Uses of Actinides:
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U-235 in Nuclear Reactors.
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Thorium in Breeder Reactors.
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As per the latest CBSE 2025 Syllabus, class 12 D and F Block Elements chapter has been numbered as chapter 4, earlier it used to be chapter 8.
NCERT Solutions Class 12 Chapter 4 d and f-block elements PDF : Download PDF For Free
Students must download the d and f block NCERT PDF from the link given below. It covers the solutions to all the NCERT textbook questions and helps students understand the concepts clearly. By practicing from this PDF, students can score high in their CBSE Board exam and entrance exams like NEET and JEE Main.
Class 12 Chemistry D and F block Elements NCERT Solution PDF: Download Free PDF
Class 12 Chapter 4 The d- and f- block Elements NCERTSolutions: Intext Questions ons
The d and f block Element Chapter 4 intext questions are based on topics such as transition elements, Lanthanoid contraction, oxidation states, ferromagnetic, Bohr magneton (BM), aqueous solutions, oxides and oxoanions of metal, Inner Transition Elements, lanthanoid contraction, and actinoid contraction. The intext questions are provided after completion of each topic. Solving these questions will help to know how well you have understood the topics. Students must seek the help of a teacher to clear the concept before moving forward. Below are the NCERT Solutions for d and f block elements intext questions.
| Q 8.1 Silver atom has completely filled d orbitals (4d 10) in its ground state. How can you say that it is a transition element? |
| Ans The elements which have partially filled d or f subshells in any common oxidation state are called as the transition elements. Silver (the Atomic number is 47 and electronic configuration is [Kr] 4d105s1) has a completely filled 4d orbital in its ground state but has two oxidation states (+1, +2). In the +1 oxidation state, an electron is removed from the s-orbital and in +2 oxidation state, one electron from d-orbital is also removed. Thus, the d-orbital now becomes partially filed (4d9). Hence, it is a transition element. |
| Q 8.2 In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomisation of zinc is the lowest, i.e., 126 kJ mol–1. Why? |
| Ans The enthalpy of atomization depends on the strength of the metallic bonding. Stronger the metallic bonding, greater is the enthalpy of atomization. The metallic bonding is strong when there are more unpaired electrons in the atom. All transition metals (except Zn, electronic configuration: [Kr] 3d10 4s2), have at least one unpaired electron that is responsible for their stronger metallic bonding. Since the Zn atom does not have an unpaired electron, the metallic bonding is weak and hence the enthalpy of atomization is low. |
| Q 8.3 Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why? |
| Ans Manganese (Z = 25) exhibits the largest number of oxidation states. This is because its electronic configuration is 3d54s2. Because it has the maximum number of electrons (5 d electrons and 2s electrons) to easily lose and share. Therefore, it can exhibit an oxidation state of +2 to +7. The compounds are as follows: Mn(0) as Mn(s), Mn(II) as MnO, Mn(II,III) , Mn etc. |
| Q 8.4 The E V (M2+/M) value for copper is positive (+0.34V). What is possible reason for this? (Hint: consider its high ∆aH V and low ∆hydH V ) |
| Ans The E0(M2+/M) value of a metal depends on the energy changes involved in the following reactions: 1. Sublimation energy: The energy needed to convert one mole of atoms from a solid state to gaseous 2. Ionization energy: The energy supplied to remove electrons from one mole of atoms, which are in the gaseous 3. Hydration energy: The energy emitted to hydrate one mole of Now, copper has a high ionisation energy and low hydration energy. Hence, the E0(M2+/M) value for copper is positive. |
Commonly asked questions
8.27 For M2+/M and M3+/M2+ systems the E V values for some metals are as follows: Cr 2+/Cr - 0.9V Cr 3 /Cr 2+ -0.4 V Mn2+/Mn -1.2V Mn3+/Mn2+ +1.5 V Fe2+/Fe -0.4V Fe3+/Fe2+ +0.8 V Use this data to comment upon:
(i) The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+
(ii) The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
8.37 What are alloys? Name an important alloy which contains some of the lanthanoid metals. Mention its uses.
8.21 Explain giving reasons:
(i) Transition metals and many of their compounds show paramagnetic behaviour.
(ii) The enthalpies of atomisation of the transition metals are high.
(iii) The transition metals generally form coloured compounds.
(iv) Transition metals and their many compounds act as good catalyst.
8.7 Which is a stronger reducing agent Cr2+ or Fe2+ and why ?
8.6 Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?
8.9 Explain why Cu+ ion is not stable in aqueous solutions?
8.5 How would you account for the irregular variation of ionisation enthalpies (first and second) in the first series of the transition elements?
8.8 Calculate the ‘spin only’ magnetic moment of M2+(aq) ion (Z = 27).
8.48 What can be inferred from the magnetic moment values of the following complex species ?
|
Example |
Magnetic moment |
|
[K4 [Mn(CN)6] |
2.2 |
|
[Fe(H2O)6]2+. |
5.3 |
|
K2 [MnCl4] |
5.9 |
8.1 Silver atom has completely filled d orbitals (4d 10) in its ground state. How can you say that it is a transition element?
8.3 Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
8.45 Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following points:
(i) Electronic configurations
(ii) Oxidation states
(iii) Ionisation enthalpies
(iv) Atomic sizes.
8.43 Compare the chemistry of the actinoids with that of lanthanoids with reference to: (i) electronic configuration (ii) oxidation states and (iii) chemical reactivity.
8.35 Give examples and suggest reasons for the following features of the transition metal chemistry:
(i) The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.
(ii) A transition metal exhibits highest oxidation state in oxides and fluorides.
(iii) The highest oxidation state is exhibited in oxoanions of a metal.
8.25 Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with: (i) iodide (ii) iron(II) solution and (iii) H2S
8.10 Actinoid contraction is greater from element to element than lanthanoid contraction. Why?
8.13 Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
8.11 Write down the electronic configuration of: (i) Cr3+ (iii) Cu+ (v) Co2+ (vii) Mn2+ (ii) Pm3+ (iv) Ce4+ (vi) Lu2+ (viii) Th4+
8.20 What are the different oxidation states exhibited by the lanthanoids?
8.16 Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.
8.22 What are interstitial compounds? Why are such compounds well known for transition metals?
8.31 How would you account for the following:
(i) Of the d 4 species, Cr2+ is strongly reducing while manganese(III) is strongly oxidising.
(ii) Cobalt(II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
(iii) The d 1 configuration is very unstable in ions.
8.30 Compare the chemistry of actinoids with that of the lanthanoids with special reference to:
(i) Electronic configuration
(ii) Atomic and ionic sizes
(iii) Oxidation state
(iv) Chemical reactivity.
8.12 Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
8.15 What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of their atoms : 3d3 , 3d5 , 3d8 and 3d4 ?
8.4 The E V (M2+/M) value for copper is positive (+0.34V). What is possible reason for this? (Hint: consider its high ?aH V and low ?hydH V )
8.14 To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
8.38 What are inner transition elements? Decide which of the following atomic numbers are the atomic numbers of the inner transition elements : 29, 59, 74, 95, 102, 104.
8.28 Predict which of the following will be coloured in aqueous solution? Ti3+, V3+ , Cu+ , Sc 3+, Mn2+, Fe 3+ and Co 2+. Give reasons for each.
8.36 Indicate the steps in the preparation of: (i) K2Cr2O7 from chromite ore. (ii) KMnO4 from pyrolusite ore.
8.34 Calculate the number of unpaired electrons in the following gaseous ions: Mn3+ , Cr3+, V3+ and Ti3+. Which one of these is the most stable in aqueous solution?
8.39 The chemistry of the actinoid elements is not so smooth as that of the lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.
8.24 Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
8.42 Name the members of the lanthanoid series which exhibit +4 oxidation states and those which exhibit +2 oxidation states. Try to correlate this type of behaviour with the electronic configurations of these elements.
8.44 Write the electronic configurations of the elements with the atomic numbers 61, 91, 101, and 109.
8.18 What are the characteristics of the transition elements and why are they called transition elements? Which of the d-block elements may not be regarded as the transition elements?
8.29 Compare the stability of +2 oxidation state for the elements of the first transition series.
8.23 How is the variability in oxidation states of transition metals different from that of the non transition metals? Illustrate with examples.
8.26 Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with (i) iron(II) ions (ii) SO2 and (iii) oxalic acid? Write the ionic equations for the reactions.
8.46 Write down the number of 3d electrons in each of the following ions: Ti2+, V2+ , Cr3+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+ and Cu2+. Indicate how would you expect the five 3d orbitals to be occupied for these hydrated ions (octahedral).
8.19 In what way is the electronic configuration of the transition elements different from that of the non transition elements?
8.41 Use Hund’s rule to derive the electronic configuration of Ce3+ ion, and calculate its magnetic moment on the basis of ‘spin-only’ formula.
8.17 What is lanthanoid contraction? What are the consequences of lanthanoid contraction?
8.47 Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
8.32 What is meant by ‘disproportionation’? Give two examples of disproportionation reaction in aqueous solution.
8.2 In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomisation of zinc is the lowest, i.e., 126 kJ mol–1. Why?
8.33 Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
8.40 Which is the last element in the series of the actinoids? Write the electronic configuration of this element. Comment on the possible oxidation state of this element.
Benefit of using NCERT Solutions for Class 12 Chemistry Chapter 4
The benefits of Class 12 Chemistry chapter 4 NCERT solutions are as follows.
- Enhance concept understanding: The solutions to the complex questions are explained in a simple way for the understanding of students. Better understanding of the question and solutions will make the concept clear.
- Improve Problem solving skills: Solving the NCERT Class 12 d and f block questions with the help of and solutions will improve the way of solving the questions.
- Revision and Practice: This is the best study material for the preparation of the exam. Solving the question will help in self-assessment and focus on the weaker topics.
NCERT Chemistry Chapter 4 The d and f Block Elements – FAQs
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