How did later atomic models differ from John Dalton's solid-sphere model?

John Dalton’s model, proposed in the early 19th century, envisioned the atom as an indivisible, solid sphere. Later models fundamentally changed this view by revealing that atoms have a complex internal structure consisting of subatomic particles.1

Key developments that diverged from Dalton’s model include:

• Thomson Atomic Model: Following the discovery of the electron, J.J. Thomson proposed that atoms were not indivisible but contained negatively charged electrons embedded within a sphere of positive charge, often called the "plum pudding" model.21
• Rutherford Atomic Model: Experiments with alpha particles demonstrated that atoms are mostly empty space with a tiny, dense, positively charged nucleus at the center, around which electrons orbit.34
• Bohr Atomic Model: To address the instability of the Rutherford model, Niels Bohr postulated that electrons occupy specific, quantized energy levels or shells, moving in stable orbits rather than spiraling into the nucleus.51
• Quantum Atomic Model: Modern theory, based on the Schrödinger equation, describes electrons not as orbiting planets, but as existing in regions of probability, and incorporates the neutron within the nucleus.31