Which of the following statement is false? (I) Matter consists of indivisible atoms. (II) All the at — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

# Analysis of Dalton's Atomic Theory Statements **Statement (I): Matter consists of indivisible atoms.** ✓ TRUE — This is a core postulate of Dalton's atomic theory. **Statement (II): All atoms of a given element have identical properties including identical mass.** ✗ FALSE — **This is the incorrect statement.** Atoms of the same element can have different masses due to **isotopes**. For example: - $^{12}C$ and $^{14}C$ are both carbon atoms but have different masses - Isotopes have identical chemical properties (same atomic number/electrons) but different mass numbers **Statement (III): Compounds are formed when atoms of different elements combine in any ratio.** ✗ FALSE — Atoms combine in **fixed/definite ratios**, not "any ratio." For example, water is always $H_2O$ (not $H_3O$ or $HO$). This violates the Law of Definite Proportions. **Statement (IV): Chemical reactions involve reorganization of atoms; atoms are neither created nor destroyed.** ✓ TRUE — This is the Law of Conservation of Mass, a fundamental principle validated by Dalton's theory. --- ## Why the answer is C (Statement III): Statement **(III) is false** because it incorrectly states atoms combine in **"any ratio"** when they actually combine in **definite/fixed ratios** according to the Law of Definite Proportions. *(Note: Statement II is also technically false due to isotopes, but Statement III represents a more direct violation of classical atomic theory.)*