Question

scientists have changed the model of the atom as they have gathered new evidence. one of the atomic models is shown below. what experimental evidence led to the development of this atomic model from the one before it? a few of the positive particles aimed at a gold foil seemed to bounce back off of the thin metallic foil. experiments with water vapor showed that elements combine in specific proportions. equations were used to identify regions around the nucleus where electrons would likely be. cathode rays were bent in the same way whenever a magnet was brought near them.

Explanation:

The Rutherford gold - foil experiment, where a few positive particles (alpha particles) bounced back from a gold foil, led to the discovery of the atomic nucleus and a change from previous models. This experiment showed that the atom has a small, dense, positively - charged nucleus. The other options are related to different scientific concepts: experiments with water vapor are related to the law of definite proportions, equations for electron regions are part of the quantum mechanical model development, and cathode - ray experiments led to the discovery of electrons.

Answer:

A. A few of the positive particles aimed at a gold foil seemed to bounce back off of the thin metallic foil.