The question is incomplete, The complete question is;
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?
Answer:
A few of the positive particles aimed at a gold foil seemed to bounce back.
Step-by-step explanation:
This model of the atom was proposed by Ernest Rutherford and was called the planetary model of the atom.
This model is based on an experiment using a gold foil on which alpha particles were focused. Most of the alpha particles passed through the foil. Some of the alpha particles were scattered at large angles and a few seemed to bounce back.
This led to the conclusion that the atom has a massive positive core around which electrons move as planets move around the sun.