Question

In the late 1800s, experiments using cathode ray tubes led to the discovery of the
(1) electron (3) positron
(2) neutron (4) proton

Answer 1

J. J. Thomson discovered a negatively charged particles called electrons during those experiments. 

Answer 2

Answer;

- Electrons

In the late 1800s, experiments using cathode ray tubes led to the discovery of the electrons.

Explanation;

-J.J. Thompson discovered an electron, the first of the subatomic particles, using the cathode ray tube experiment. He found that many different metals release cathode rays, and that cathode rays were made of electrons, very small negatively charged particles.