What does Dalton's atomic theory primarily state about the nature of matter?

Dalton's atomic theory primarily states that all matter is made of atoms. This foundational concept revolutionized the understanding of chemistry by introducing the idea that atoms are the basic building blocks of matter. Each element is composed of its own type of atom, and these atoms combine in various ways to form molecules and compounds.

Dalton proposed that atoms are indivisible and indestructible, which supports the assertion that all matter consists of atoms rather than smaller units like molecules. This is a crucial distinction because it emphasizes that the distinct properties of different substances arise from the unique combinations and arrangements of differing atoms.

While the other statements touch on related ideas, they do not accurately capture the core principle of Dalton's theory. For instance, the notion that all matter is made of molecules is incorrect because molecules are formed primarily from atoms bonded together. The claim that all atoms can be divided into smaller particles contradicts Dalton’s assertion about the indivisibility of atoms. Finally, stating that all atoms of different elements are identical is also misleading because, according to Dalton, it is precisely the differences in atoms of various elements that account for the diversity of matter in the universe. Thus, the primary assertion of Dalton's atomic theory holds that all matter is fundamentally constituted by atoms.