Dalton's ideas that atoms cannot be divided into smaller parts was disproved by the discovery of the_____

is it electrons

I suspect that finding that electrons surround a nucleus would be fatal for the hypothesis of indivisibility :)

lol so am i right

I think so.

And can you imaging that if the discovery of electrons didn't do enough damage that the discovery of protons and neutrons would do it in. Having said all of that, let's not condemn the theory without recognizing that with just a slight word change here and there the four main parts of Dalton's hypothesis still are true. The core concepts were valid. That word change I mention is that ELEMENTS are composed of atoms and ELEMENTS are not infinitely divisible but ultimately consist of individual ATOMS of that element.

so is it electrons or what?

Hellplpppp

It is JJ THOMPSON