In thomson’s experiment, why was the glowing beam repelled by a negatively charged plate?

1.) the beam contained lightweight particles which were easily deflected.

2.) the beam contained negatively charged particles.

3.) the beam contained positively charged particles.

I would have to say that the answer to this question is 2.) The beam contained negitively charged particles.

Since - and - pull away because it's both negative, same goes for + and +. But - and + do. The beam was negative, hense why it pulled away.. therefore the answer to the question is B. Or in your case 2.).

I really hope I have explained this well enough for you. If you need anymore help just message me, okay?

They are all decomposition reactions.