CBSE Class 12 Chemistry The d and f Block Elements Assignment

CBSE Class 12 Chemistry The d and f Block Elements Assignment. Students are advised to refer to the attached assignments and practise them regularly. This will help them to identify their weak areas and will help them to score better in examination. Parents should download and give the assignments to their children for practice.

Q.1-Explain briefly how +2 oxidation states becomes more and more stable in the first half of the first row transition elements with increasing atomic number.
Ans.1-In M2+ ions, 3d-orbitals get occupied gradually as the atomic number increases. Since, the number of empty d-orbitals decreases, the stability of cations increases from Sc2+ to Mn2+ .Mn2+ is most stable as all d-orbitals are singly occupied.
Q.2- Explain why transition elements have many irregularities in their electronic configurations?
Ans.2-In the transition elements, there is a little difference in the energy of (n-1) d-orbitals and nsorbitals.
Thus, incoming electron can occupy either of shell. Hence, transition elements exhibit many irregularities in their electronic configurations.
Q.3-What are different oxidation states exhibited by Lanthanides?
Ans.3-The common stable oxidation state of lanthanides is +3.However some members also show oxidation states of +2 & +4.
Q.4-How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
Ans.4-The transition elements use its (n-1)d, ns and np orbital and the successive oxidation states differ by unity. For example, Mn shows all the oxidation states from +2 to +7. On other hand non transition elements use its ns, np and nd orbitals and the successive oxidation states differ by two units e.g. Sn2+, Sn4+ etc.
Q.5- Why do transition elements show variable oxidation states?
Ans.5- The transition elements show variable oxidation state due to small energy difference between (n-1) d &ns orbital as a result both (n-1)d &ns electrons take part in bond formation.
Q.6-Why are Mn2+ compounds more stable than Fe2+ compounds towards oxidation to +3 state?
Ans.6-The electronic configuration of Mn2+ is [Ar] 3d5, i.e. all five d-orbitals are singly occupied.
Thus this is stable electronic configuration and further loss of electron requires high energy .on other hand side the electronic configuration of Fe2+is [Ar] 3d6, i.e. Loss of one electron requires low energy.
Please click the link below to download CBSE Class 12 Chemistry The d and f Block Elements Assignment



Click to View or Download pdf file
Click for more Chemistry Study Material

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

NEP Transforming India Quiz

As a part of Shikshak Parv celebration, an online quiz competition on National Education Policy 2020 will be organized by the Ministry of Education, Govt. of India, from 5 th September to 25th September 2020 in order to create awareness about NEP among all stakeholders...

National Online Painting Championship

The National Mission for Clean Ganga, Ministry of Jal Shakti in collaboration with Kalantar Art Trust is organizing KALANTAR-2020: National Online Painting Championship with the aim to provide a platform to youth and school children to demonstrate their artistic skills...

Conduct of the practical work during the lockdown

CBSE has advised schools to follow the Alternative Calendar developed by NCERT to continue education during the lockdown through alternative modes to achieve learning outcomes. Schools have reportedly started using these calendars and other prescribed pedagogical...

Revised SOP preventive measures followed while conducting examinations

Revised SOP on preventive measures to be followed while conducting examinations to contain spread of COVID-19 issued by Ministry of Health & Family Welfare Examination centres are frequented by large number of students (as well as their parents) and staff till the...

Mathematical Literacy Free Practice Book for Students

With a larger goal to promote 21st century skills such as critical thinking and problem solving, the Central Board of Secondary Education has shared a Mathematical Literacy: Practice Book for Students. This Work Book is designed to allow learners of classes 7th to 10th...

Training of CBSE School Teachers on Olabs

Training of CBSE School Teachers on Olabs in collaboration with C-DAC Mumbai: OLabs is a platform jointly developed by the Ministry of Electronics and Telecommunications, Government of India, CDAC, and Amrita University to facilitate a virtual experience of CBSE...

Studies Today