Write a paragraph or two about how and why has the atomic idea/model changed (Greeks 1600-1930)
The evolution of the atomic idea/model from the Greeks (around 400 BC) to the early 20th century witnessed significant changes driven by advancements in scientific thinking and experimental evidence. The Greeks, notably Democritus and Leucippus, proposed the concept of atoms as indivisible, indestructible particles that make up all matter. However, their ideas were purely philosophical and lacked empirical evidence. Fast forward to the late 18th century, the discovery of chemical elements and the formulation of the Law of Definite Proportions by Antoine Lavoisier laid the foundation for understanding the composition of matter at the atomic level. The advent of Dalton's atomic theory in the early 19th century provided a more scientific framework for explaining chemical reactions and the behavior of atoms.
However, it was only in the late 19th and early 20th centuries that further breakthroughs revolutionized atomic understanding. With the discovery of subatomic particles, such as electrons, protons, and neutrons, by J.J. Thomson, Ernest Rutherford, and James Chadwick, respectively, the atomic model began to take shape. Thomson proposed the "plum pudding" model, where electrons were embedded within a positively charged sphere. Rutherford's gold foil experiment revealed that most of the atomic mass was concentrated in a tiny, dense nucleus, leading to the development of the nuclear model of the atom.
The emergence of quantum mechanics in the early 20th century, spearheaded by scientists like Max Planck, Albert Einstein, and Niels Bohr, brought about radical transformations in the atomic model. Quantum mechanics introduced the concept of energy quantization at the atomic level, explaining the discrete energy levels of electrons and their behavior as both particles and waves. Bohr's quantum model of the hydrogen atom, with electrons occupying specific energy orbits, successfully explained the emission and absorption spectrum of atoms.
Overall, the atomic idea/model underwent profound changes over centuries due to the convergence of theoretical advancements, empirical discoveries, and experimental evidence. From the philosophical notions of ancient Greeks to the modern-day understanding of subatomic particles and quantum mechanics, our comprehension of the atom has progressively evolved, aligning with empirical observations and deeper explorations into the atomic realm.