daatrack.blogg.se - 9th class chemistry solved exercises chapter 3

🔹 The mass of an atom of an element is called its atomic mass.

Atomic radius of smallest atom in hydrogen is 0.37 x 10-¹⁰m or 0.037 nm.

🔹 Atoms are very small and hence can’t be seen even through very powerful microscope. 🔹 According to modern atomic theory, an atom is the smallest particle of an element which takes part in chemical reaction such that during the chemical reaction, the atom maintain its identity, throughout the chemical or physical change.

The relative number and kinds of atoms are constant in a given compound.

Atom combine in the ratio of small whole numbers to form compounds.

Atoms of different elements have different mass and chemical properties.

Atoms of an element have identical mass and chemical properties.

Atom are indivisible particles, which can’t be created or destroyed in a chemical reaction.All matter is made up of very tiny particles called ‘Atoms’.

❇️ Postulates of Dalton’s atomic theory :. 🔹 Based upon laws of chemical combination, Dalton’s Atomic Theory provided an explanation for the Law of Conservation of Mass and Law of Constant Composition.

🔹 According to this law, “A pure chemical compound always contain the same elements combined together in the same proportion by mass irrespective of the fact from where the sample has been taken or from which procedure has it been produced.”