Question

Choose the Incorrect Statement about Dalton's Atomic Theory

• A. Compounds are formed when atoms of different elements combine in any ratio
• B. All the atoms of a given element have identical properties including identical mass
• C. Matter consists of indivisible atoms
• D. Chemical reactions involve recorganization of atoms

Answer 1

The Correct Option is A

Dalton’s Atomic Theory states that compounds are formed when atoms of different elements combine in a fixed, simple, whole number ratio, not in
any ratio. This forms the basis of the law of definite proportions. Therefore, statement (1) is incorrect. Other statements correctly describe the indivisible nature of atoms and their behavior in chemical reactions according to Dalton’s theory.

Answer 2

Step 1: Recall Dalton’s Atomic Theory
John Dalton proposed his atomic theory in 1808 to explain the laws of chemical combination. The main postulates of his theory are:
1. Matter is made up of indivisible atoms.
2. Atoms of the same element are identical in mass and properties.
3. Atoms of different elements have different masses and properties.
4. Compounds are formed when atoms of different elements combine in simple whole-number ratios.
5. Chemical reactions involve rearrangement of atoms; atoms are neither created nor destroyed.

Step 2: Examine the given statement
The statement says:
"Compounds are formed when atoms of different elements combine in any ratio."

This contradicts Dalton’s fourth postulate. According to Dalton, atoms combine in fixed, simple whole-number ratios to form compounds. For example:
- Water (H₂O) → 2 atoms of hydrogen combine with 1 atom of oxygen.
- Carbon dioxide (CO₂) → 1 atom of carbon combines with 2 atoms of oxygen.

Atoms do not combine in arbitrary or “any” ratios; the composition of a compound is definite and fixed.

Step 3: Conclusion
Hence, the given statement is incorrect because it violates the principle of fixed ratios of combination in Dalton’s Atomic Theory.

Final answer

Compounds are formed when atoms of different elements combine in any ratio