Question

Recall all the models you described in task 1. Think about the results each model would predict for Thomson’s experiment. Which atomic models does Thomson’s experimental evidence support? Explain why these models are compatible with the experimental results.

Answer 1

J.J. Thomson's "plum pudding" model represented the atom as a sphere of positive charge with embedded electrons, while Rutherford's gold foil experiment disproved this model by revealing a dense positive nucleus, which led to his planetary model of the atom.

Step-by-step explanation:

Thomson's Experimental Evidence and Atomic Models

Thomson's experiment led to the discovery of the electron, which provided evidence for his "plum pudding" model of the atom. In this model, the atom is envisioned as a sphere of positive charge with electrons (the "plums") scattered throughout it, like raisins in a pudding. This model supported the idea that atoms were divisible and contained internal structure, with the electrons being held within the positive sphere.

Rutherford's gold foil experiment, however, challenged the plum pudding model. His unexpected observation of alpha particles deflecting at large angles after hitting a thin gold foil suggested that a small, dense, positively charged nucleus existed at the center of the atom, with electrons orbiting around it. Therefore, Rutherford's planetary model replaced Thomson's model, proposing a central nucleus surrounded by an electron cloud.

Answer 2

J.J. Thomson’s experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged “soup.”