Final answer:
If the nucleus in Rutherford's experiment had been negatively charged, the positively charged alpha particles would have been attracted to the nuclei, causing more absorption and less dramatic scattering, thus suggesting a different atomic structure.
Step-by-step explanation:
If the nucleus in Rutherford’s gold foil experiment had a negative charge, the results would be significantly different. Since alpha particles are positively charged, they were repelled by the positively charged nuclei of the gold atoms in the actual experiment. This repulsion is what caused some alpha particles to be scattered backwards after striking the gold foil. However, if the nucleus had been negatively charged, the positively charged alpha particles would have been attracted to the nuclei rather than repelled.
This attraction would likely result in a significantly higher number of alpha particles being absorbed by the foil or scattered at much smaller angles, rather than bouncing off at large angles or back in the direction they came from. The attraction between the negative nucleus and the positive alpha particles would mean that an alpha particle would be drawn inward toward the nucleus upon approach, potentially resulting in more collisions and less scattering. Consequently, Rutherford would not have observed the few dramatic deflections that led him to propose a small, dense, positively charged nucleus. Instead, the pattern of scattering observed on the detection screen would have suggested a very different atomic structure.