Question

which of daltons ideas about the atom did j.j. thomsons experiment disprove?
○ it disproved that atoms are divisible.
○ it disproved that atoms are indivisible.
○ it disproved that atoms contain protons.
○ it disproved that atoms contain electrons.

Explanation:

Dalton's atomic theory proposed that atoms are indivisible. J.J. Thomson's discovery of electrons (through cathode - ray experiments) showed that atoms can be divided into smaller particles (electrons and the rest of the atom). The first option is incorrect as Dalton thought atoms were indivisible, and Thomson's work showed they are divisible, not that they are divisible (the statement is misphrased in terms of what was disproved). The third option is incorrect because Thomson's experiment was about electrons, not protons. The fourth option is incorrect because Thomson discovered electrons, so he didn't disprove that atoms contain electrons.

Answer:

B. It disproved that atoms are indivisible.