Question

Describe Thomson’s “plum pudding” model of the atom, and then explain how the results of Rutherford’s gold foil experiment resulted in a change to the atomic model.

Answer 1

Answer:

While the plum pudding model suggested that electrons in an atom are embedded in a positively charged substrate, Rutherford's experiment concluded that it is only the core of an atom that is positively charged around which the electrons move in fixed orbits.  

Explanation:

J. J. Thomson's 'plum-pudding' model suggested that atoms are composed of positive and negatively charged particles. The electrons that are negatively charged are embedded (like the plums in a pudding) in a sea of positive charge.

This theory was disproved by Rutherford via his gold foil experiment in which he bombarded positively charged alpha particles onto a thin gold foil. He observed that while most of the particles passed through the foil some of them completely retraced their path. This led to two major conclusions:

- Most of the space inside the atom is empty

-The mass of the atom is concentrated in the positively charged core called the nucleus.

Answer 2

Thomson saw the atom to be a spherical cloud of positive proton matter with electrons dispersed throughout it. Then the gold foil experiment is when Rutherford shot alpha particles at a sheet of gold foil and when there was deflection he concluded there was a dense part in the center of an atom with he called the nucleus made up of neutrons and protons.