Neils Bohr and Atomic Theory
In ancient Greek the word atom meant the smallest indivisible particle that could be conceived. The atom was thought of as indestructible; in fact, the Greek word for atom means "not divisible." Knowledge about the size and make up of the atom grew very slowly as scientific theory progressed. What we know/theorize about the atom now began with a core theory devised by Democrotus, a Greek philosopher who proposed that matter consisted of various types of tiny discrete particles and that the properties of matter were determined by the properties of these particles. This core theory was then modified and altered over years by Dalton, Thompson, Rutherford, Bhor, and Chadwick. The atoms original structure was simple, but as more and more research was done the atom became more complex and puzzling
The five atomic theories of the past two centuries represent the sudden advancement of science in modern times. Beginning with a basic theory on the behavior of atoms to the current model, some changes have been made, and some ideas are still the same. Ancient Greek philosophers believed that everything was made up of invisible particles called atoms. Since then the theory of atoms did not progress until 18
The first level can only accommodate two electrons, the second can hold up to eight electrons, the third can hold up to eight-teen, and so on. When an alpha particle strikes ZnS it produces a flash of light. A theory never becomes fact until all of the bugs are wiped out, if this is true then this atomic theory is well on its way to becoming the facts about atoms. Danish physicist Neils Bohr used new knowledge about the radiation emitted from atoms to develop a model of the atom significantly different from Rutherford's model. This led Thomson to conclude that there were an equal number of both particles present in the atom. The laws of classical physics work perfectly well on the scale of everyday objects, but on the tiny atomic scale, the laws of quantum mechanics apply. However, when conceiving this theory, Bohr was forced to make some startling conclusions. Classical physics could not account for these observations, and scientists began to realize that they needed to take a new approach. Twelve years later Lord Ernest Rutherford was experimenting with alpha particles. It is much like that of our planetary system. Dalton's atomic theory is based on four concepts. Based on the work of William Crookes and his "Crookes tube" (Cathode-ray tube), Thomson discovered a negative charged particle was the cause of the light produced by the cathode-ray tube. He shot a stream of them at a piece of gold foil surrounded by zinc-sulfide.