NCERT Solutions for Class 12 Chemistry Chapter 4 The d and f Block Elements - Free PDF Download
Chapter 4 Chemistry Class 12 deals with the d and f block of the modern periodic table. The chapter is essential to understand the electronic configuration and the general characteristics of transition elements, oxidization, and chemical reactivity.
For students appearing in the board exams, this chapter is crucial as several essential questions are set from this chapter. In this regard, the Class 12 Chemistry Chapter 4 NCERT solutions come as a great help.
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Important Topics Covered in NCERT Solutions Class 12 Chemistry Chapter 4 The d- and f-block Elements
Students are suggested to go through the following topics and the subsequent sub-topics from NCERT Class 12 Chemistry Chapter 4 thoroughly for their exam preparation.
Position of d-block Elements in the Periodic Table
Position of f-block Elements in the Periodic Table
Electronic Configuration of d-block Elements
General Properties of the d-block Elements or Transition Elements
Transition Elements Important Compounds
Lanthanoids and Actinoids
Applications of d and f-block Elements
The d-and f-Block Elements Chapter at a Glance - Class 12 NCERT Solutions
d-Block Elements
d-block elements are those in which the last electron goes to (n-1) d-orbitals.
General electronic configurations of d-block elements is : ns1-2, (n-1)d1-10
Transition metals have high values of melting and boiling points which are due to the presence of strong metallic bonding in these metals.
Due to lanthanide contraction, atomic radii for the elements of 3rd transition series are almost equal to those for the elements of 2nd transition series.
The values of ionisation energies increase as we move from left to right in each series.
Except for Cu, E°red values for other metals of 1st transition series are negative.
Excepting a few metals, most of the metals show several oxidation states. This is due to the fact that (n-1)d and ns orbitals have almost the same energy.
Transition metal ions which contain partially filled d-orbitals are usually coloured. The colour arises because of d0-d10 transition. Transition metal ions with d0 or d10 configuration
are colourless because d-d transition is not possible in such ions.
Transition metals form interstitial compounds.
Many transition metals and their alloys and compounds act as catalysts in many chemical reactions.
f-Block Elements
The elements in which the last electron enters f-orbital of (n- 2)th shell are called f-block elements. f-block elements are of two types lanthanides and actinides.
General electronic configuration of f-block elements is ns2, (n-1)d0-1, (n-2)f1-14
+ 3 oxidation state (O.S.) is the most stable O.S. of lanthanides.
There is a steady decrease in atomic and ionic (M3+ ions) radii of lanthanides. This steady decrease in atomic and ionic radii is called lanthanide contraction.
Magnetic moment value of lanthanides and actinides is calculated by considering both orbital spin contribution. Μeff value is given by μeff = 4S (S+1)+L(L+1) B.M, here S spin quantum number and L= orbital quantum number
Mischmetal is an important alloy of lanthanides. It contains 90% lanthanides (La= 40%, Ce and other lanthanides= 50%) , Fe = 5% and traces of other elements like C, S, Al, Ca.
The actinide elements lying beyond U (Np-93 to Lw-103) are called trans-uranic or trans-uranium elements.
Unlike lanthanides, actinides show a large number of oxidation states.
Actinides have lower values of ionisation energies.
Most of actinide halides form complex compounds with alkali metal halides. The degree of complex formation for the ions decreases as : M4+ > MO2 2+ > M3+ > MO2+.
Thorium is used in atomic reactors and in the treatment of cancer. Uranium is used as a nuclear fuel. Plutonium is used as a fuel for atomic reactors as well as for making atomic bombs.
d-and f-Block Elements
FAQs on NCERT Solutions for Class 12 Chemistry Chapter 4 - The D And F Block Elements
1. How Helpful is the NCERT Solution for Understanding f and b Block Elements?
Vedantu’s experts create the NCERT Chemistry answer for f and b block elements. This material will be of great assistance to students taking board examinations since it will remove any doubts based on the basics of the chapters using examples, diagrams, and illustrations.
The significant problems concerning the electrical configuration, oxidation, and chemical reactivity of inner transition metals are thoroughly discussed. Students will be able to study the periodic table placements of d- and f-block elements.
Apart from general features, students will study subjects such as trends in higher oxidation state instability and trends in $M^{3+}/M^{2+}$ Standard Electrode Potential.
2. Provide Some of the Important NCERT Questions on f and b Block Elements.
Some of the critical questions for both short and very short questions from f and b block elements are given below.
Explain why Cu+ ion is not stable in aqueous solution.
What is the stronger reducing agent Cr2+ or Fe2+, and why?
Why is the highest oxidization state of metal exhibited in its oxide and fluoride only?
Which of the 3d series of transition metals exhibits the largest numbers of oxidized states and why?
The silver atom has filled the d orbit (4d10) in its ground state, then how can you state that it is a transition element?
3. What are the Important NCERT Topics and Subtopics of Chapter f and b Block Elements?
The important NCERT topics and subtopics for the d and f block chapter are given below:
Position in the periodic table.
Electronic configuration of the d block element.
General properties of Transition elements (d block).
Some important compounds of transition elements.
The Lanthanoids.
The Actinoids.
Some application of d block and f block elements.
The NCERT solutions cover all the chapters through exercises and detailed illustrations. Nearly 38 questions are solved extensively by expert teachers that generate improved understanding. Apart from this, there is also a section of solved examples that helps the students in clarifying the concept of d and f block elements.
4. How do you define f block Class 12 Chapter 4 Chemistry?
The elements that make up the f-block are those in which the 4 f and 5 f orbitals are gradually filled in the last two long periods; these elements are official members of group 3, from which they were separated to create the f-block of the periodic table. For additional modules regarding the same, please visit the Vedantu site (vedantu.com) or download the Vedantu app. Practice all the related problems diligently in order to grasp the concepts well.
5. Where would you group Lanthanum in the f block?
Lanthanum cannot be grouped in the f block as it is a d block element. Lanthanum is the first element in the third transition series, and it begins to fill the 5d orbitals. As a result, the configuration is [Xe]5d1 6s2. Only the following element (cerium) fills the 4f orbitals. Hence it will be grouped among the d block elements of the periodic table. Modules relating to this topic or other topics covered in this chapter may be found on the Vedantu website (vedantu.com) or the Vedantu app.
6. Which is the best Solution book for NCERT Class 12 Chapter 4 Chemistry?
The best solution book is of Vedantu as it is easily accessible and free of charge on the Vedantu website. Click on it to obtain the PDF version of the NCERT Class 12 Chemistry Chapter 4 answers. If you want further assistance in better-comprehending topics and achieving high scores in examinations and admission exams, the Vedantu website and app can assist you.
7. Why do we mention f block elements below?
The f-block elements are 28 elements broad, and if they were placed alongside the transition metals in their atomic number position, the periodic table would be too large to fit on normal A4 paper or a page in a textbook, thus they were placed below the other groups. As a result, it is mentioned below the other parts separately. Modules pertaining to this or other topics covered in this chapter are available on the Vedantu website or app.
8. What are the challenging chapters in Class 12 Chapter 4 Chemistry?
In Chemistry, each chapter has its own set of distinct hurdles, however there are a few chapters that provide many obstacles, which is normal for most students. The p block components are regarded as a more difficult chapter in the NCERT Class 12 Chemistry syllabus when compared to the other chapters in the subject. As a result, it is critical to read this chapter with care and caution in order to fully comprehend all of the principles.
