NCERT books offer a number of problems which students can practice to assess their learning and prepare for the examinations. Practicing a variety of questions helps to strengthen the fundamentals of a topic which makes students efficient in solving different questions asked in exams based on that particular topic. Therefore, students are suggested to solve all the NCERT questions and learn to write perfect solutions which will help them score good marks in exams.
To help students find the right approach to solve the class 11 Chemistry NCERT questions, we have collated detailed and accurate solutions. Our subject experts have reviewed these NCERT solutions to provide you the error free content which will help to make an effective preparation for the annual exams.
CBSE Class 11 Chemistry NCERT Solutions for Chapter- Classification of Elements and Periodicity in Properties
Here we are providing NCERT solutions for CBSE Class 11 Chemistry Chapter 3, Classification of Elements and Periodicity in Properties. All the questions have been solved in the most appropriate and simple way so as to help students access the right study material for the exam preparation.
Students may download the NCERT solutions for Class 11 Chemistry in PDF format.
Main topics discussed in Class 11 Chemistry chapter- Classification of Elements and Periodicity in Properties, are:
- Need of classification of elements
- Basis of periodic classification
- Modern periodic law and the present form of the periodic table
- Nomenclature of elements with atomic numbers > 100
- Electronic configurations of elements
- Electronic configurations and types of elements in s-, p-, d-, f- blocks
- Metals, non-metals and metalloids
- Periodic trends in properties of elements
Trends in physical properties
Periodic trends in chemical properties
Periodic trends and chemical reactivity
Some of the questions and their solutions from NCERT Solutions for Class 11: Classification of Elements and Periodicity in Properties, are as follows:
Q. On what basis did Mendeleev classify the elements in his periodic table and did he continue with that?
Solution: Mendeleev classified the elements in his periodic table into periods and groups in order of their increasing atomic weight. The elements with similar characteristics were placed in the same group. However, he did not continue with the same mode of classification for long. He observed that arranging the elements rigidly in order of their increasing atomic weights, resulted in anomalies as some elements did not fit within this design. Therefore, the order of atomic weights was ignored in some cases. For example, the atomic weight of iodine is lower than that of tellurium. Still Mendeleev placed tellurium (in Group VI) before iodine (in Group VII) just because the characteristics of iodine are quite similar to fluorine, chlorine, and bromine.
Q. Elements in the same group have similar physical and chemical properties. Explain why?
Solution: The physical and chemical properties of elements rely upon the number of valence electrons. Elements present in the same group have the same number of valence electrons. Hence, the elements present in the same group have similar physical and chemical properties.
Q. What makes cations smaller and anions larger in radii than their parent atoms?
Solution: A cation has a lesser number of electrons than its parent atom. However, its nuclear charge remains the same. Consequently, the attraction between the electrons and the nucleus is more in a cation than in its parent atom. Hence, a cation becomes smaller in size than its parent atom.
On the other hand, an anion has one or more electrons than its parent atom. This results in an increased repulsion among the electrons, thereby decreasing the effective nuclear charge. As such, the distance between the valence electrons and the nucleus is greater in anions than in it's the parent atom. That is why, an anion is larger in radius than its parent atom.
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