Which part of dalton's theory did thomson's findings dispute? atoms of different elements have different masses. atoms of the same element have the same mass. the atom is the smallest known particle of matter. compounds contain atoms of more than one element?

the atom is the smallest known particle of matter.

Explanation:

Postulates of Dalton's atomic theory:

Atom are indivisible and are the smallest constituents of matter.

Atoms of same element have similar mass.

Atoms of different elements have different mass.

Elements combine with each other in whole number ratios to form compounds.

Thomson found the negatively charged particles called electrons and told they are embedded in a soup of positively charged sphere.

Thus the part of dalton's theory that thomson's findings dispute is Atom are indivisible and are the smallest constituents of matter.