Get complete NCERT Solutions for 9 Science 4. Structure of The Atom with detailed explanations. Easy-to-understand answers to help students study effectively and score better.
Get complete NCERT Solutions for 9 Science 4. Structure of The Atom with detailed explanations. Easy-to-understand answers to help students study effectively and score better.
9 Science Chapter 4. Structure of The Atom - Chapter Review
Preparing for exams becomes easier with Chapter Review. Whether you are studying for board exams or mid-term exams,
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4. Structure of The Atom
Chapter Review
Chapter Review:
- Atoms and molecules are the fundamental building blocks of matter.
- The existence of different kinds of matter is due to different atoms constituting them.
- The electron is identified by J.J. Thomson.
- Electrons, protons and nutrons are sub atomic particles.
- E. Goldstein in 1886 discovered the presence of new radiations in a gas discharge and called them canal rays.
- Electrons carry Negative (-) charge.
- Protons carry Positive (+) charge.
- Nutrons carry No any charge.
- J.J. Thomson was the first one to propose a model for the structure of an atom.
- The electrons revolve around the nucleus in well-defined orbits.
- The size of the nucleus is very small as compared to the size of the atom.
- Protons and Nutrons are situated in nucleus of atom.
- Orbits or shells of an atom are represented by the letters K, L, M, and N.
- J. Chadwick discovered another sub atomic particles named nutron.
- The number of protons present in nucleus of an atom is known as atomic number. i.e Atomic mass = total number of protons in nucleus os an atom.
- The sum of the masses of protons and neutrons present in the nucleus is known as Atomic Mass.
- The maximum number of electrons present in a shell is given by the formulla 2n2.
- The electrons present in the outermost shell of an atom are known as the valence electrons.
- The number of valence electrons present in outer most shell of an atom is known as its valency.
- The mass number is defined as the sum of the total number of protons and
neutrons present in the nucleus of an atom.
- The atoms of the same element, having the same atomic number but differentmass numbers is called its isotopes.
- Protium, Deuterium and tritium are isotopes of Hydrogen.
- Many elements consist of a mixture of isotopes. Each isotope of an element is a pure substance.
- The chemical properties of isotopes are similar but their physical properties are different.
- 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.
- Atoms of different elements with different atomic numbers, which have the same mass number, are known as isobars.
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📘 Why Chapter Review are Important?
Chapter Review are created by experts to give step-by-step explanations. Around 60–70% of exam questions are based on NCERT concepts.
Our 9 Science Chapter 4. Structure of The Atom solutions help you understand the core concepts and practice effectively.
✍️ Quick Revising Points as Notes in Page-1
Revision is the key to exam success. Our notes for 9 Science highlight important formulas, key definitions,
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📚 NCERT Exercise Solutions
Every NCERT chapter ends with exercises, and solving them is crucial. Our Chapter Review include complete solutions for
9 Science Chapter 4. Structure of The Atom exercises. With step-by-step answers, you gain clarity and
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📝 Additional Important Questions & Answers
To boost your preparation, we also provide additional important questions with answers. These are prepared from previous year board papers,
sample papers, and important concepts of Chapter 4. Structure of The Atom. Practicing these ensures you are well-prepared for both board and mid-term exams.
🎯 Useful for Board & Mid-Term Exams
Our Chapter Review are useful for both board exams and mid-term exams.
For 9 Science, we provide notes, exercises, and important Q&A so that you can
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🌟 Final Words
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