Question

Consider the following statements regarding postulates of Dalton's atomic theory.

1. Atoms are divisible particles.

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

Which among the above statements is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Answer 1

Correct Answer - Option 2 : 2 only

The correct answer is 2 only.

• John Dalton, a British chemist provided the basic theory about the nature of matter.
• His theory was based on the laws of chemical combination.

• Dalton’s atomic theory provided an explanation for the law of conservation of mass and the law of definite proportions.
• Law of Conservation of Mass- Mass is neither created nor destroyed in chemical reactions.
• Law of definite proportions- Every chemical compound contains fixed and constant proportions (by mass) of its constituent elements.
• According to Dalton’s atomic theory all matter is composed of small particles called atoms. The postulates of this theory may be stated as follows:-
  • All matter is made of very tiny particles called atoms, which participate in chemical reactions.
  • Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction. Hence, statement 1 is incorrect.
  • Atoms of a given element are identical in mass and chemical properties.
  • Atoms of different elements have different masses and chemical properties.
  • Atoms combine in the ratio of small whole numbers to form compounds.
  • The relative number and kinds of atoms are constant in a given compound. Hence, statement 2 is correct.