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4. Structure of The Atom Science class 9 in English Medium ncert book solutions Additional -Questions 2
4. Structure of The Atom Additional -Questions 2 – Complete NCERT Book Solutions for Class 9 Science (English Medium). Get all chapter explanations, extra questions, solved examples and additional practice questions for 4. Structure of The Atom Additional -Questions 2 to help you master concepts and score higher.
4. Structure of The Atom Science class 9 in English Medium ncert book solutions Additional -Questions 2
NCERT Solutions for Class 9 Science play an important role in helping students understand the concepts of the chapter 4. Structure of The Atom clearly. This chapter includes the topic Additional -Questions 2, which is essential from both academic and examination point of view. The solutions provided here are prepared strictly according to the latest NCERT syllabus and follow the guidelines of CBSE to ensure accuracy and relevance. Each question is explained in a simple and student-friendly manner so that learners can grasp the concepts without confusion. These NCERT Solutions are useful for regular study, homework help, and exam preparation. All textbook questions are solved step by step to improve problem-solving skills and conceptual clarity. Students of Class 9 studying Science can use these solutions to revise important topics, understand difficult questions, and practise effectively before examinations. The chapter 4. Structure of The Atom is explained in a structured way, making it easier for students to connect the theory with the topic Additional -Questions 2. By studying these updated NCERT Solutions for Class 9 Science, students can build a strong foundation, boost their confidence, and score better marks in school and board exams.
4. Structure of The Atom
Additional -Questions 2
Additional And Important Questions With solutions:
Q – Write the results of Rutherford’s particle scattering experiment.
A – The following observations were made: Most of the fast moving particles passed straight through the gold foil.
- Some of the α-particles were deflected by the foil by small angles.
- Surprisingly one out of every 12000 particles appeared to rebound.
5. Compare all the proposed models of an atom given in this
chapter.
6. Summarise the rules for writing of distribution of electrons in various shells for the first eighteen elements.
Q – Describe Thomson’s model of the atom.
A – Thomson proposed that:
- An atom consists of a positively charged sphere and the electrons are embedded in it.
- The negative and positive charges are equal in magnitude. So, the atom as a whole is electrically neutral.
Q – Define valency by taking examples of silicon and oxygen.
A – The electrons present in the outermost shell of an atom are known as the valence electrons. This number of valence electrons is called valency.
Example of silicon and oxygen
Number of electrons in silicon = 14
Electronic configuration = 2, 8, 4
The number of valence electrons = 4
Hence valency = 4
Example of oxygen
Number of electrons in oxygen = 8
Electronic configuration = 2, 6
The number of valence electrons = 8 – 6 = 2
Hence valency = 2
Q – Define atomic number.
A – The number of protons presence in nucleus of an atom is known as atomic number.
Q – Define atomic mass.
A – The sum of number of protons and neutrons presence in nucleus of an atom is known as atomic mass.
Q – Define isotopes.
A – The atoms of an element are called isotopes of that element which has equal atomic number but different atomic mass.
Q – Define isobar.
A – The atoms of an element are called isobar of that element which
Q – Differentiate between isotopes and isobars.
A -
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isotopes |
isobars |
( )
|
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Q – Write three applications of isotopes.
A – Three applications of isotopes.
- An isotope of uranium is used as a fuel in nuclear reactors.
- An isotope of cobalt is used in the treatment of cancer.
- An isotope of iodine is used in the treatment of goitre.
See other sub-topics of this chapter:
1. Chapter Review 2. Text-book Questions 3. Additional -Questions 4. Additional -Questions 2 5. Additional -Questions 3