Choose the Incorrect Statement about Dalton's Atomic Theory

We need to identify the incorrect statement about Dalton's Atomic Theory.

Dalton's Atomic Theory states:

(i) Matter consists of indivisible atoms.

(ii) All atoms of a given element have identical properties including identical mass.

(iii) Chemical reactions involve reorganization of atoms (atoms are neither created nor destroyed).

(iv) Compounds are formed when atoms of different elements combine in fixed, simple whole number ratios.

Option 1: "Chemical reactions involve reorganization of atoms" - This is correct per Dalton's theory.

Option 2: "Matter consists of indivisible atoms" - This is correct per Dalton's theory.

Option 3: "Compounds are formed when atoms of different elements combine in any ratio" - This is INCORRECT. Dalton stated atoms combine in fixed simple ratios, not "any ratio."

Option 4: Combines "any ratio" with "identical mass" - while the "any ratio" part is wrong, the "identical mass" part is actually a correct postulate of Dalton.

Option 3 directly contradicts Dalton's law of definite proportions by stating "any ratio" instead of "fixed ratio."

The correct answer is Option 3.