Question

In Rutherford's experiment, a thin gold foil was bombarded with alpha particles. According to 'Thomson's Plum-Pudding' model of the atom, what should have happened?
(A) All the alpha particles would have been deflected by the foil.
(B) All the alpha particles should have bounced straight back from the foil.
(C) Alpha particles should have passed through the foil with little or no deflection.
(D) Alpha particles should have become embedded in the foil.

Answer 1

Hint: To solve this question we first need to know more about Thomson's plum pudding model of an atom. The plum pudding model of an atom given by J J Thomson stated that the atom can be considered as a uniformly distributed positively charged sphere embedded with negative charge electrons making the atom neutral.

Complete answer:
Now, we know that according to the plum pudding model of an atom by Thomson, an atom is a charge-neutral sphere. So, when alpha ($\alpha$) particles, which are positively charged (identical to $H{e}^{2+}$), are passed through this charge-neutral sphere atom, they should be able to pass through with little or no deflection.
Hence when a thin gold foil is bombarded with alpha particles, the alpha particles should be able to pass through to no or little deflection.

So, the answer to the question is option (C).

Note:
It should be noted that the plum pudding model of an atom proposed by JJ Thomson was a failure. So, after conducting the gold foil experiment and analyzing the observations, Rutherford atomic model was suggested which stated that
- An atom has a concentrated region of positive charge at the center known as the nucleus.
- The negative charge circle around the nucleus in an orbit.
- The positive and negative charge particles are bonded by strong electrostatic forces of attraction.