Question

Which of the assumptions/postulates that John Dalton made about the atom have been proven to be false?

A. Atoms are indivisible and indestructible.
B. Atoms of the same element are identical.
C. Atoms combine in simple whole-number ratios.
D. Atoms have a nucleus composed of protons and neutrons.

Answer 1

Dalton's assumptions that atoms are indivisible and that atoms of the same element are identical have been proven false due to the discovery of subatomic particles and isotopes.

Step-by-step explanation:

Among the assumptions or postulates made by John Dalton about the atom, a few have been proven to be false. The assumption that atoms are indivisible and indestructible (A) has been shown to be incorrect. Atoms can be further subdivided into smaller particles called protons, neutrons, and electrons.

Moreover, the postulate that atoms of the same element are identical (B) has been challenged by the discovery of isotopes, which are atoms of the same element with different masses and densities, such as the isotopes of chlorine with mass numbers 35 and 37.