CBSE Class 12 Chemistry The D And F Block Elements Notes Set C

Download CBSE Class 12 Chemistry The D And F Block Elements Notes Set C in PDF format. All Revision notes for Class 12 Chemistry have been designed as per the latest syllabus and updated chapters given in your textbook for Chemistry in Class 12. Our teachers have designed these concept notes for the benefit of Class 12 students. You should use these chapter wise notes for revision on daily basis. These study notes can also be used for learning each chapter and its important and difficult topics or revision just before your exams to help you get better scores in upcoming examinations, You can also use Printable notes for Class 12 Chemistry for faster revision of difficult topics and get higher rank. After reading these notes also refer to MCQ questions for Class 12 Chemistry given on studiestoday

Revision Notes for Class 12 Chemistry Unit 08 The d- and f-Block Elements

Class 12 Chemistry students should refer to the following concepts and notes for Unit 08 The d- and f-Block Elements in Class 12. These exam notes for Class 12 Chemistry will be very useful for upcoming class tests and examinations and help you to score good marks

Unit 08 The d- and f-Block Elements Notes Class 12 Chemistry

CBSE Class 12 Chemistry notes and questions for The d and f Block Elements Part C. Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.

d – AND f – BLOCK ELEMENTS

Electronic Configuration of Transition Metal/Ions

The d-block element is called transition metal if it has partly filled d-orbitals in the ground state as well as in its oxidised state.

The general electronic configuration of transition metal is (n–1) d1–10ns1–2Exceptions in electronic configuration are due to (a) very little engery difference between (n–1) d and ns orbitals and (b) extra stability of half filled and completely filled orbitals in case of Cr and Cu in 3d series.

Cr : Is2 2s2 2p6, 3s2 3p6 4s1 3d5

Cu : Is2 2s2 2p6, 3s2 3p6 4s1 3d10

To write the electronic configuration of Mn+, the electrons are first removed from ns orbital and then from (n - 1) d orbitals of neutral, atom (if required). For example, the electronic configuration of Cu+, Cu2+ and Cr3+ are respectively

3d10 4s°, 3d9 4s° and 3d3 4s°.

The following questions can be answered with the help of above.

(i) Scandium (Z = 21) is a transition element but zinc (Z = 30) is not.

(ii) Copper (Z = 29) and silver (Z = 47) both have fully filled d-orbitals i.e., (n - 1) d10. why are these elements are regarded as transition elements?

(iii) Which of the d-block elements are not regarded as transition elements?

UNDERSTANDING Δfus H Θ,vap HΘAND Δa HΘ

In transition metals unpaired (n - l)d electrons as well as ns electrons take part in interatomic bonding. Larger the number of unpaired (n - 1) d electrons, the stronger is the interatomic bonding and large amount of energy is required to overcome the interatomic interaction.

class_12_chemistry_concept_65

The following questions can be explained using the above reasoning.

(i) Which has higher m.p.? V (Z = 23) or Cr (Z = 24) ?

(ii) Explain why Fe (Z = 26) has higher m.p. than cobalt (Z = 27).

Metals of second (4d) and third (5d) transition series have greater enthalpies of atomisation than corresponding elements of first transition series on account of more frequent metal metal bonding due to greater spatial extension of 4d and 5d orbitals than 3d orbitals.

LANTHANOID CONTRACTION AND ITS CONSEQUENCE

The 4f orbitals screen the nuclear .charge less effectively because they are large and diffused. The filling of 4f orbitals before 5d orbitals results in the gradual increase in effective nuclear charge resulting in a regular decrease in atomic and ionic radii. This phenomenon is called lanthanoid contraction. The corresponding members of second and third transition series have similar radii because the normal size increase down the group of d-block elements almost exactly balanced by the lanthanoid contraction.

This reasoning is applied in answering the following questions.

(i) Elements in the’following pairs have identical (similar) radii : Zr/Hf, Nb/Ta and Mo/W. Explain why?

(ii) Why do Zr and Hf have very similar physical and chemical properties and occur together in the same mineral?

VARIATION IN IONISATION ENTHALPY

With the filling of (n - 1) d orbitals effective nuclear charge increases resulting in the increase in first ionisation enthalpy. There are some irregular variations.

The first ionisation enthalpy of chromium is lower because the removal of one electron produces extra stable d5 configuration and that of zinc is higher because the removal of electron takes place from fully filled 4s orbital. Second ionization enthalpy of Zn (Δi H2 = 1734 kj)/mol) is lower than second ionization enthalpy of Cu (1958 kj/mol). This is because removal of second electron in Zn produces stable d10 configuration while the removal of second electron in Cu disrupts the d10 configuration with a considerable loss in exchange energy to from less stable d9 configuration.

Cr = 3d5 4s1

Zn = 3d10 4s2; Zn2+ = 3d10

Cu = 3d10 4s1; Cu2+ = 3d9

Please click the link below to download pdf file for CBSE Class 12 Chemistry notes and questions for The d and f Block Elements Part C.

z More Study Material for Class 12 Chemistry
Class 12 Chemistry Full Study Material For Boards Revision

CBSE Class 12 Chemistry Unit 08 The d- and f-Block Elements Notes

We hope you liked the above notes for topic Unit 08 The d- and f-Block Elements which has been designed as per the latest syllabus for Class 12 Chemistry released by CBSE. Students of Class 12 should download and practice the above notes for Class 12 Chemistry regularly. All revision notes have been designed for Chemistry by referring to the most important topics which the students should learn to get better marks in examinations. Our team of expert teachers have referred to the NCERT book for Class 12 Chemistry to design the Chemistry Class 12 notes. After reading the notes which have been developed as per the latest books also refer to the NCERT solutions for Class 12 Chemistry provided by our teachers. We have also provided a lot of MCQ questions for Class 12 Chemistry in the notes so that you can learn the concepts and also solve questions relating to the topics. We have also provided a lot of Worksheets for Class 12 Chemistry which you can use to further make yourself stronger in Chemistry.

Where can I download latest CBSE Class 12 Chemistry Unit 08 The d- and f-Block Elements notes

You can download notes for Class 12 Chemistry Unit 08 The d- and f-Block Elements for latest academic session from StudiesToday.com

Are the revision notes available for Unit 08 The d- and f-Block Elements Class 12 Chemistry for the latest CBSE academic session

Yes, the notes issued for Class 12 Chemistry Unit 08 The d- and f-Block Elements have been made available here for latest CBSE session

Is there any charge for the Class 12 Chemistry Unit 08 The d- and f-Block Elements notes

There is no charge for the notes for CBSE Class 12 Chemistry Unit 08 The d- and f-Block Elements, you can download everything free of charge

Which is the best online platform to find notes for Unit 08 The d- and f-Block Elements Class 12 Chemistry

www.studiestoday.com is the best website from which you can download latest notes for Unit 08 The d- and f-Block Elements Chemistry Class 12

Where can I find topic-wise notes for Class 12 Chemistry Unit 08 The d- and f-Block Elements

Come to StudiesToday.com to get best quality topic wise notes for Class 12 Chemistry Unit 08 The d- and f-Block Elements