Describe the rutherford's model of an atom.
Answers
Answer:
Explanation:
A thin section of gold foil was placed in front of the slit, and a screen coated with zinc sulfide to render it fluorescent served as a counter to detect alpha particles. As each alpha particle struck the fluorescent screen, it produced a burst of light called a scintillation, which was visible through a viewing microscope attached to the back of the screen. The screen itself was movable, allowing Rutherford and his associates to determine whether or not any alpha particles were being deflected by the gold foil.
Rutherford gold-foil experiment
Rutherford gold-foil experiment
In 1909 Rutherford disproved Sir J.J. Thomson's model of the atom as a uniformly distributed substance. Because only very few of the alpha particles in his beam were scattered by large angles after striking the gold foil while most passed completely through, Rutherford knew that the gold atom's mass must be concentrated in a tiny dense nucleus.
Most alpha particles passed straight through the gold foil, which implied that atoms are mostly composed of open space. Some alpha particles were deflected slightly, suggesting interactions with other positively charged particles within the atom. Still other alpha particles were scattered at large angles, while a very few even bounced back toward the source. (Rutherford famously said later, “It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you.”) Only a positively charged and relatively heavy target particle, such as the proposed nucleus, could account for such strong repulsion. The negative electrons that balanced electrically the positive nuclear charge were regarded as traveling in circular orbits about the nucleus. The electrostatic force of attraction between electrons and nucleus was likened to the gravitational force of attraction between the revolving planets and the Sun. Most of this planetary atom was open space and offered no resistance to the passage of the alpha particles. The Rutherford model supplanted the “plum-pudding” atomic model of English physicist Sir J.J. Thomson, in which the electrons were embedded in a positively charged atom like plums in a pudding. Based wholly on classical physics, the Rutherford model itself was superseded in a few years by the Bohr atomic model, which incorporated some early quantum theory.