The nuclear model of the atom, proposed by Ernest Rutherford in 1911, describes the atom as having a small, dense nucleus at its center. This nucleus contains positively charged protons and neutral neutrons, while negatively charged electrons orbit around the nucleus in defined paths. This model replaced the earlier plum pudding model, which suggested that electrons were distributed throughout a positively charged "soup." The nuclear model helped explain the results of Rutherford's gold foil experiment, demonstrating that most of an atom's mass is concentrated in the nucleus, leading to a better understanding of atomic structure.