Prior to Rutherford's gold foil experi-ment, the 'plum pudding' model of the atom represented atomic structure. In this model, the atom is composed of elec-trons interspersed within a positive cloud of charge. If this were the correct model of the atom, predict how the results of Rutherford's experiment would have been different. (a) The alpha particles would pass right through the gold foil with little to no deflection. (b) Most of the alpha particles would be deflected back toward the source. (c) Most of the alpha particles would be absorbed by the atom and neither pass through nor be deflected from the gold foil.

Key Concepts

Plum Pudding Model

The plum pudding model, proposed by J.J. Thomson, suggests that atoms are composed of negatively charged electrons embedded within a positively charged 'soup' or cloud. This model implies that the positive charge is diffuse and not concentrated in any specific location, leading to the expectation that alpha particles would pass through with minimal interaction.

Rutherford's Gold Foil Experiment

Rutherford's gold foil experiment involved firing alpha particles at a thin sheet of gold foil. The unexpected results, where some particles were deflected at large angles, led to the conclusion that atoms have a small, dense nucleus containing most of their mass and positive charge, contradicting the plum pudding model and suggesting a more complex atomic structure.

Alpha Particle Interaction

Alpha particles are positively charged and relatively massive compared to electrons. In the context of atomic models, their interaction with atomic structures depends on the distribution of charge within the atom. If the plum pudding model were accurate, alpha particles would experience minimal deflection due to the diffuse positive charge, whereas the actual results indicated a concentrated nucleus that could significantly deflect some particles.