Question

what did ernest rutherford expect to happen when he aimed a beam of particles at a
the particles would deflect at sharp angles or completely back toward the emitter.
the particles would pass through the foil undisturbed.
the particles would deflect at right angles after hitting the foil.
the particles would be deflected slightly after passing through the foil.

Explanation:

Rutherford expected, based on the then - prevailing plum - pudding model of the atom, that the particles would pass through the foil undisturbed. The plum - pudding model suggested a uniform distribution of positive and negative charges in the atom, so there was no reason for significant deflections.

Answer:

The particles would pass through the foil undisturbed.