Class 9 Science Atoms and Molecules

Class 9 Science Atoms and Molecules

Atoms And Molecules chapter of class 9 science is based on the study of different typed Atoms and Molecules. While studying in the class 9 science chapter it is important to know about these topics which includes:-

Laws of Chemical combinations

Dalton’s Atomic theory

What is an Atom?

What is an Molecule?

Writing a Chemical Formulae

Law of conservation of Mass etc

Class 9 science chapter 3 is typically titled “Atoms and Molecules” and covers the following concepts:

  • The concept of atoms as the building blocks of matter.
  • The discovery of atoms and molecules and the contributions of scientists like John Dalton, J.J Thomson, and Ernest Rutherford to the atomic theory.
  • The structure of atoms, including the nucleus and electrons and the concept of atomic number and atomic mass.
  • The concept of isotopes and their properties.
  • The concept of molecules and the difference between atoms and molecules.
  • The concept of chemical bonding, including ionic, covalent, and metallic bonding.
  • The concept of chemical formulas, including molecular and empirical formulas.
  • The concept of chemical equations and the law of conservation of mass.
  • The concept of acids, bases, and salts and their properties.
  • The concept of chemical reactions and the formation of new substances.
  • It may vary based on the curriculum and board you are following.

The main topics covered in the chapter “Atoms and Molecules” are:

  • Definitions of the Atoms and Molecules.
  • Atomic theory and the discovery of atoms
  • Structure of atoms, including the nucleus and electrons
  • Atomic number and atomic mass
  • Isotopes and their properties
  • Difference between atoms and molecules
  • Types of chemical bonding, including ionic, covalent and metallic bonding
  • Chemical formulas, including molecular and empirical formulas
  • Chemical equations and the law of conservation of mass
  • Acids, bases, and salts and their properties
  • Chemical reactions and the formation of new substances
  • Molecular mass and molar mass
  • Avogadro’s number and molar volume of gases
  • Collision theory and rate of chemical reactions


It may vary based on the curriculum and board you are following.

After analyses of this chapter you can also go through the PDF Notes of next Chapter of Class 9 Science ” Chapter -4 Structure of the Atom.”

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