Question

what evidence did thomson have to support his hypothesis? (check all that apply)
no matter what metal used for the disk, the particles produced were identical.
no matter how large or small the sample, the ratio of masses of the elements in the compound is always the same.
the particles had about 1/2000 the mass of a hydrogen atom, the lightest atom.
compounds have a fixed composition.

Explanation:

• Thomson's experiments with cathode - ray tubes showed that the particles (electrons) produced were the same regardless of the metal used for the disk (this is evidence for the existence of a fundamental particle).
• He also measured the charge - to - mass ratio of these particles and found that their mass was about \(1/2000\) the mass of a hydrogen atom (the lightest atom at that time), which further supported the idea of a new sub - atomic particle.

• The statements about the ratio of masses of elements in a compound and compounds having a fixed composition are related to the law of definite proportions (a concept in chemistry about compounds in general, not directly related to Thomson's hypothesis about electrons).

Answer:

• No matter what metal used for the disk, the particles produced were identical.
• The particles had about 1/2000 the mass of a hydrogen atom, the lightest atom.