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The NCERT Solutions for class 9 Science Chapter 4 Structure Of The Atom have been provided in the article below. Some of the Class 9 Science Chapter 4 important concepts include:
NCERT Solutions for Class 9 Science Chapter 4
Download: NCERT Solutions for Class 9 Science Chapter 4 pdf
Important Topics in Class 9 Science Chapter 4 Structure of the Atom
Structure of Atom consists of three basic particles: Electrons, Protons, and Neutrons. Nucleus is the center of the atom and contains protons. Protons are positively charged, whereas Neutrons have no charge. In absence of electrical charge, the neutron is not repelled by a cloud of electrons or by a nucleus. Thus, it becomes a useful tool for probing the structure of atoms. Outermost parts of atoms are called Electron Shells and contain negatively charged electrons.
Atomic Number
Atomic number can be expressed by the number of protons or electrons present in the atom. Atomic number is responsible to determine the type of an element. It is represented by the letter Z.
| Example: Calculate the mass number of a given element which has an atomic number of 15 and a total number of protons of 15. Solution: As we already know the formula, the mass number can be determined, |
Mass Number
Mass number, or atomic mass number, of an element can be defined as the total number of protons found in the atom of an element. The mass number of elements is important because it helps determine atomic mass.
| The Formula of Mass Number: Mass number = The Atomic mass number + the total number of neutrons |
Subatomic Particles of an Atom
Subatomic particles are those that help compose atoms. These are the constituent units of all matter, including Electrons, Protons and Neutrons.
| Example: Name and define the three Subatomic Particle of an Atom. Solution: The three primary subatomic particles are Electrons, Protons, and Neutrons. Electrons are known for its negatively charged particles, while protons are positively charged. Meanwhile, neutrons are neutral as because they do not carry any charge. |
Proton Mass
Protons are stable subatomic particles possessing positive charge. It is considered equal in magnitude to a unit of electron charge, alongside a rest mass of 1.67262 × 10−27 kg. Proton Mass cn be represented using the sign mp.
| Example: How is Proton Mass calculated? Solution: Proton Mass can be evalutated using three steps: These are the three methods:
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| Important Science Study Guides | ||
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| Named Reactions | Physics Constants | Difference between in biology |
| Difference between in chemistry | Difference between in physics | Periodic Table |
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