Which of the following postulates of Dalton's atomic theory is NOT considered true based on modern scientific understanding?

• A. Atoms cannot be created, divided, or destroyed in chemical reactions.
• B. All matter is composed of tiny, indivisible particles called atoms.
• C. Compounds are formed by the combination of atoms of different elements in fixed ratios.
• D. Atoms of a given element are identical in mass and properties.

Answer: (D)

Verified step by step guidance

1. Review each postulate of Dalton's atomic theory carefully to understand its original claim.
2. Recall that modern atomic theory has refined some of Dalton's ideas based on experimental evidence, such as the discovery of subatomic particles and isotopes.
3. Identify the postulate stating that "Atoms cannot be created, divided, or destroyed in chemical reactions." Modern science agrees that atoms are not created or destroyed in chemical reactions, but they can be divided into subatomic particles, so this postulate is mostly true in the context of chemical reactions.
4. Consider the postulate "All matter is composed of tiny, indivisible particles called atoms." Modern science shows that atoms are divisible into protons, neutrons, and electrons, so this postulate is not entirely true.
5. Focus on the postulate "Atoms of a given element are identical in mass and properties." Modern understanding shows that atoms of the same element can have different masses due to isotopes, so this postulate is NOT considered true today.