What is the plum pudding model different from nuclear model?

The plum pudding model and the nuclear model are two different models that describe the structure of an atom. The plum pudding model, also known as the Thomson model, was proposed by J.J. Thomson in 1904. It suggests that an atom consists of a positively charged sphere with negatively charged electrons embedded in it, much like plums in a pudding.

On the other hand, the nuclear model, also known as the Rutherford model, was proposed by Ernest Rutherford in 1911. According to this model, an atom consists of a small, dense, and positively charged nucleus surrounded by electrons orbiting around it. The nucleus contains most of the atom's mass, while the electrons are responsible for its chemical properties.

The main differences between the plum pudding model and the nuclear model are:

1. Structure of the Nucleus: The plum pudding model does not have a distinct nucleus, while the nuclear model has a central positively charged nucleus.

2. Distribution of Charge: In the plum pudding model, the positive and negative charges are evenly distributed throughout the atom. In contrast, in the nuclear model, the positive charge is concentrated in the nucleus, and the negative charge is distributed in the electron cloud.

3. Stability of the Atom: The plum pudding model cannot explain why atoms are stable. According to the model, the negatively charged electrons should be attracted to the positively charged sphere and collapse into it. On the other hand, the nuclear model explains the stability of atoms by introducing the concept of a nucleus that holds the electrons in orbit around it.

4. Scattering Experiments: The plum pudding model could not explain the results of Rutherford's gold foil experiment, which showed that most of the mass and positive charge of an atom were concentrated in a small, dense nucleus. The nuclear model, however, successfully explained the observed scattering of alpha particles in the experiment.

5. Discovery of Subatomic Particles: The nuclear model led to the discovery of subatomic particles such as protons and neutrons within the nucleus. These particles were not accounted for in the plum pudding model.

In summary, the plum pudding model and the nuclear model are two distinct models of atomic structure. The nuclear model, with its central nucleus and orbiting electrons, is the currently accepted model as it accurately explains various experimental observations and phenomena related to atomic structure and behavior.