Atoms and Molecules Class 9 Handwritten Notes. In this post, we have shared Atoms and Molecules Class 9 Notes PDF.
Atoms and Molecules Class 9 Handwritten Notes
Class 9 Science Handwritten Notes [All Chapters]
Laws of Chemical Combination –
1. Law of Conservation of mass – Mass can neither be created nor destroyed in a chemical reaction.
2. Law of Constant proportion – Elements are always Present in definite proportions by mass in a
chemical substance. For example & Hydrogen and oxygen are present in water in a ratio of 1:8. Thus, if 9g of water is decomposed, 1g of hydrogen and 8g of oxygen are always obtained.
Dalton Atomic Theory – All matter whether it is an element, a compound, or a mixture consists of tiny
invisible particles called atoms.
Postulates of Dalton atomic theory –
(1) The matter is made up of tiny particles called atoms that cannot be divided.
(2) Atoms are never formed or destroyed during a Chemical reaction.
(3) Atoms of an element have the same nature. They have the same size, mass, and character (4) Atoms of different elements exhibit variant nature. They do not have the same characteristics.
(5) Atoms foom compounds by combining in a ratio of whole numbers
(6) A Compound Contains constant numbers and kinds of atoms.
What is an Atom?
Atoms are the building blocks of matter. Just like bricks are the building blocks of a building.
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