Question

j.j. thomson and cathode rays
in the late 1800s, a scientist named j.j. thomson was especially interested in a phenomenon he observed in cathode ray tubes. cathode ray tubes are glass tubes filled with gas connected to a power source. the cathode ray tube creates a bright beam that moves from one end of the tube to the other. in fact, cathode rays look a lot like lightning! since the gas was very hard to energize, thomson suspected that something smaller than atoms might be causing the lightning - like beam. he designed several experiments to determine what was in these beams. some of those experiments are summarized in the table below.

from these experiments, thomson deduced that the beams were made up of tiny, negatively charged particles much smaller than atoms. we call these particles electrons. they are subatomic particles, which means they are even smaller than an atom! in latin, sub means \under\ or \beneath.\
after his experiments, thomson thought that the atom was a solid, positively charged sphere with tiny, negatively charged particles embedded throughout it. not all scientists agreed with thomsons model of the atom.
text chunk 2: write the main idea in your own words or images. (if you are not sure, reread and annotate.)

Explanation:

The text is about J.J. Thomson's experiments with cathode rays. He observed that the beam in cathode - ray tubes bent towards positively charged plates and away from negatively charged plates, indicating a negative charge. He also found that the ratio of mass to charge of the beam particles was the same regardless of the gas in the tube and much smaller than that of known atoms. From these, he deduced that the beam was made of tiny negatively charged particles (electrons) smaller than atoms. After the experiments, he proposed a model of the atom as a positively charged sphere with embedded negative electrons.

Answer:

J.J. Thomson's experiments on cathode - ray tubes led him to discover electrons (tiny negatively charged subatomic particles) and propose an atomic model (a positively charged sphere with embedded negative electrons).