# CBSE Class 10 Science NCERT Solutions: Chapter 5, Periodic Classification of Elements

jagranjosh.com presents here the NCERT solutions for CBSE Class 10 Science chapter- Introduction to Trigonometry, in a well-structured format. All the solutions are explained by subject experts. Students having trouble solving tough Science problems can refer to these NCERT solutions.

Why to solve questions/problems given in NCERT Book?

The questions in the NCERT books are strategically placed after every conceptual paragraph to check the students’ understanding. Students should try to answer all the questions to keep a track of their performance.

Consistent practice of solving the NCERT questions helps to break the complex problems in most efficient way.

NCERT Solutions given here will help you find the right approach to all the questions given in the NCERT Book. Students may download all the NCERT Solutions for CBSE Class 10 Science chapter – Periodic Classification of Elements, in the form of PDF.

Some of the questions and their solutions from NCERT Solutions for Class 10: Periodic Classification of Elements, are as follows:

Q. What were the criteria used by Mendeleev in creating his Periodic Table?

Sol. Mendeleev's periodic table was based on the observation that the properties of elements are a periodic function of their atomic masses. This statement means that if elements are arranged in the increasing order of their atomic masses, then their properties get repeated after regular intervals.

Q. Why do you think the noble gases are placed in a separate group?

Sol. Noble gases are inert in nature. They show different properties from the all other elements. Thus, they are placed in a separate group.

Class 10 Science NCERT Exemplar Problems and Solutions

Q. How could the Modem Periodic Table remove various anomalies of Mendeleev’s Periodic Table?

Sol. Mendeleev was not able to give fixed position to hydrogen and isotopes in the periodic table. In his periodic table, the increasing atomic masses of the elements were not always regular.

Later on, it was found that a more fundamental property atomic number than atomic mass could explain periodic properties in a better manner.

Henry Moseley demonstrated that atomic number of an element could explain periodic properties in a better way than atomic mass of an element. He arranged the elements in increasing order of their atomic numbers. Then It was found that the various anomalies of Mendeleev's periodic table were removed by the modem periodic table.

Q. How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Sol. In the modern periodic table, atoms with similar electronic configurations are placed in the same column.
In a group, the number of valence electrons remains the same. Elements across a period show an increase in the number of valence electrons.

Get the complete the NCERT solutions for Class 10: Periodic Classification of Elements, from the following link:

Class 10 Science NCERT Chapter: Periodic Classification of Elements

Before solving the questions given in the Class 10 Science NCERT chapter- Periodic Classification of Elements, students should thoroughly read this chapter to grasp all the concepts explained in it. This will help you understand the problem discussed in a question and then come with an appropriate answer.

Main topics discussed in Class 10 Science chapter: Periodic Classification of Elements are:

• Need of classification of elements
• Newlands’ law of octaves
• Mendeléev’s periodic table
• Merits and demerits of Mendeléev’s periodic table
• Modern periodic table
• Position of elements in the modern periodic table
• Trends in the modern periodic table.