Question

Explain Dalton's atomic theory and explain which ideas are still true and which ideas have been proven false.

Answer 1

Dalton's atomic theory proposed that all matter consists of indivisible atoms, which combine to form compounds. While the existence of atoms and chemical combinations holds true, we now know atoms can be subdivided, are not identical even within an element due to isotopes, and can be transformed via nuclear reactions.

Step-by-step explanation:

Dalton's Atomic Theory

John Dalton's atomic theory, proposed around the early 19th century, states that all matter is composed of small, indivisible particles called atoms. Despite being over 200 years old, many aspects of this theory remain true today. However, there have been significant modifications and clarifications to the original postulates based on the advancement of scientific knowledge.

• Valid Concepts of Dalton's Theory

Dalton's theory correctly asserted the existence of atoms as the basic units of matter and that compounds are formed by the combination of different types of atoms. Atoms as fundamental particles and the idea that chemical reactions involve the rearrangement of these atoms still stand as foundational concepts in modern chemistry.

• Ideas Proven False

Over time, it has been discovered that atoms can be further subdivided into subatomic particles such as protons, neutrons, and electrons. Additionally, isotopes have shown us that all atoms of an element are not identical in mass, and through the processes of nuclear fission and fusion, atoms can be transformed, effectively creating or destroying them in terms of nuclear reactions.

Dalton also believed that atoms could not be created or destroyed in chemical reactions (the law of conservation of mass), which generally holds true for chemical reactions, but not for nuclear reactions where atoms can indeed be transformed.

• Summary of Changes to the Theory

To summarize the current understanding, while the existence of atoms and the idea that they combine to form compounds are true, Dalton's notions that atoms are indivisible, identical within an element, and cannot be created or destroyed are no longer considered valid.