Ernest Rutherford made significant contributions to the atomic theory through his groundbreaking experiments and the discovery of the atomic nucleus. In 1909, he conducted the famous gold foil experiment, where he and his team directed alpha particles at a thin sheet of gold. They expected these particles to pass through with minimal deflection, based on the plum pudding model of the atom, which proposed that atoms were uniform spheres of positive charge with electrons scattered throughout.
To their surprise, while most alpha particles did pass through the foil, a small percentage were deflected at large angles, and some even bounced back. This led Rutherford to conclude that atoms must contain a dense central core, which he called the nucleus, where most of the atom’s mass and positive charge is concentrated. This was a pivotal shift in atomic theory and laid the groundwork for the modern understanding of the atom.
Furthermore, Rutherford’s work paved the way for the discovery of the proton and changed the conceptualization of the atom from a diffuse sea of charge to a complex structure with a nucleus surrounded by orbiting electrons. His findings not only deepened our understanding of atomic structure but also influenced the way future scientists would explore the intricacies of atomic physics.