Final answer:
Option D) Atoms contain electrons, protons, and neutrons is not a statement of Dalton's atomic theory because Dalton did not account for an atom's internal structure or subatomic particles in his theory.
Step-by-step explanation:
Among the options provided, the statement that is not a part of Dalton's atomic theory is D) Atoms contain electrons, protons, and neutrons. This is because Dalton's original atomic theory did not account for the internal structure of the atom, as it was believed that atoms were the smallest indivisible units of matter. Dalton proposed his atomic theory in 1804 which included several postulates. According to Dalton, atoms of the same element are identical (A) and atoms of different elements combine in simple whole-number ratios to form compounds (B). Furthermore, atoms cannot be created or destroyed in chemical reactions (C), which refers to the law of conservation of mass. However, subsequent scientific discoveries proved that atoms could indeed be subdivided into smaller particles, namely protons, neutrons, and electrons, which was not part of Dalton's original theory.
Dalton's atomic theory also had to be revised to account for the discovery of isotopes, which are atoms of the same element with different masses. For example, chlorine has two isotopes with mass numbers 35 and 37. Moreover, with the introduction of nuclear fission and fusion techniques, it became clear that atoms could be transformed into other atoms, thus challenging the idea that they cannot be created or destroyed.