What describes the plum pudding model of an atom?

The plum pudding model of the atom is characterized by the idea that the atom is composed of a sphere of positive charge within which electrons are embedded, much like raisins scattered throughout a pudding. This model suggests that the positive charge is spread out to balance the negative charge of the electrons, resulting in an overall neutral atom.

This concept arose during the early 20th century as scientists were investigating the structure of the atom and trying to account for its overall neutrality. Unlike later models, such as the Rutherford model, which introduced the idea of a dense nucleus, the plum pudding model illustrates a more uniform distribution of positive charge throughout the atom, representing the electrons merely as points of negative charge embedded in that positive "pudding."

The other descriptions do not accurately reflect the plum pudding model. For instance, the notion of a dense nucleus surrounded by electrons corresponds to the Rutherford model, while the idea of a solid atom with no empty space does not capture the nuanced understanding of atomic structure presented by the plum pudding model. Additionally, a model showing only protons and neutrons fails to encompass the distribution of electrons that is central to the concept of the plum pudding model.