The Evolution of Atomic Models
Your understanding of atoms has come a long way from the simple ideas scientists had centuries ago. John Dalton initially described atoms as solid spheres, but this theory quickly crumbled when new evidence emerged.
In 1897, JJ Thomson discovered that atoms contained even smaller charged particles called electrons. This led to his famous "plum pudding model" - imagine a positively charged pudding with electrons scattered throughout like raisins.
However, Ernest Rutherford's gold foil experiment in 1909 completely shattered this idea. When he fired alpha particles at gold foil, most went straight through, but some bounced back dramatically. This proved atoms had a tiny, dense nucleus at their centre, surrounded by mostly empty space.
Key Point: Scientific theories change when new evidence emerges - that's how we've built our current atomic model!
The refined Bohr model then suggested electrons exist in fixed shells around the nucleus, each with specific energy levels. This model, backed by experimental evidence, closely resembles what we understand today about atomic structure.
