Which atomic model included the concept of a nucleus?

Rutherford's Atomic Model is notable for introducing the concept of a nucleus, which is a central core containing positively charged protons and neutral neutrons, surrounded by negatively charged electrons. This model emerged from Rutherford's famous gold foil experiment, where he observed that a small fraction of alpha particles were deflected at large angles when directed at a thin gold foil. This unexpected result led him to conclude that most of an atom's mass and positive charge must be concentrated in a tiny area at its center, which he termed the nucleus.

This was a significant shift from earlier models, such as Thomson's Plum Pudding Model, which proposed that atoms were composed of a diffuse cloud of positive charge with electrons embedded within it, lacking a central nucleus. Similarly, Dalton's Atomic Model conceived atoms as indivisible particles without any internal structure, and while Bohr's Atomic Model built upon Rutherford's model by introducing quantized electron energy levels, it followed the foundational understanding of the nucleus established by Rutherford. Thus, Rutherford's model clearly laid the groundwork for the understanding of atomic structure that includes the nucleus.