Question

Which of the following statements about our understanding of the structure of the atom is

true?
Dalton's atomic theory recognised the existence of isotopes as well as the synthesis of
atoms in the laboratory
In a cathode-ray tube, electrons always travel towards the negatively charged electrode.
In Mallkan's oil drop experiment, oil droplets with a negative charge fell more slowly than
droplets with a positive charge.
Rutherford's gold foil experiment confirmed the existence of protons.

Answer 1

Dalton's theory did not recognize isotopes, and in cathode-ray tubes, electrons move toward the positive electrode. Millikan's experiment showed that negatively charged droplets fall slower, and Rutherford's experiment confirmed protons' existence.

Step-by-step explanation:

Among the historical developments regarding the atomic structure, we find that Dalton's atomic theory did not initially recognize the existence of isotopes. Later scientific advancements corrected this oversight. Moreover, in a cathode-ray tube, electrons are actually attracted to the positively charged electrode, contrary to the opposite. In Millikan's oil drop experiment, it was observed that oil droplets with a negative charge fell more slowly than uncharged droplets due to the balance between gravitational and electrical forces. Rutherford's gold foil experiment was crucial as it confirmed the existence of a small, dense, positively charged nucleus, thus substantiating the presence of protons within the atom.