What is the Rutherford scattering model?

The Rutherford scattering model is a theory that describes the scattering of alpha particles by atomic nuclei.

Developed by Ernest Rutherford in 1911, the Rutherford scattering model was a groundbreaking theory that revolutionised our understanding of atomic structure. Prior to Rutherford's work, the widely accepted model of the atom was the 'plum pudding' model proposed by J.J. Thomson. This model suggested that atoms were a uniform sphere of positive charge, with negatively charged electrons embedded within it. However, Rutherford's experiments with alpha particle scattering led him to propose a different model.

Rutherford and his team fired a beam of alpha particles (which are positively charged) at a thin sheet of gold foil and observed the scattering patterns on a fluorescent screen. They expected the alpha particles to pass straight through the foil with little deflection, as predicted by the plum pudding model. However, they found that while most alpha particles did pass straight through, a small number were deflected at large angles, and some even bounced back towards the source.

This observation could not be explained by the plum pudding model. Rutherford proposed that the atom must have a small, dense, positively charged nucleus at its centre, which the alpha particles were bouncing off or being deflected by. The rest of the atom was mostly empty space, through which the alpha particles could pass straight through. This became known as the nuclear model of the atom.

The Rutherford scattering model also provided a mathematical formula to predict the distribution of scattering angles. This formula, known as the Rutherford scattering formula, is based on the principles of classical mechanics and electrostatics. It assumes that the alpha particles and the atomic nuclei interact only through the Coulomb force, which is the force between two charged particles.

In summary, the Rutherford scattering model was a significant step forward in our understanding of atomic structure. It replaced the plum pudding model with the nuclear model of the atom, and provided a mathematical framework for predicting the scattering of alpha particles by atomic nuclei.