Rutherfords-Atomic-Model.ppt

1、RutherfordsAtomic Structure Model,Calvin, Wendy, Shaun,Outline,1. What people believed before Rutherford 2. Rutherford model 3. Rutherfords model is a milestone,Before,Elements are made of extremely small particles calledatoms.,（ John Dalton17661844),Atom-model： Solid sphere, indivisible,Daltons Ato

2、mic Theory,Atom is not the smallest particle. (1897),（J.J.Thomson ,18561940）,Plum Pudding Model,negative,positive,Electron,1.Dalton （1803）,3.Rutherford （1911）,2.Thomson （1904）,Solid Sphere,Plum Pudding Model,RutherfordsModel,RUTHERFORD MODEL,PLANETARY MODEL,Rutherford Gold Foil Experiment,Alpha part

3、icle Foil of metal Fluorescent screen,Thomsons model,Rutherford model,The thickness of the material The atomic mass of the substance The velocity of the alpha particles The probability is vanishingly small,The electron cloud of an atom does not influence alpha particle scattering Much of an atoms ch

4、arge is concentrated in a relatively tiny volume at the center of the atom The mass of heavy atoms such as gold is mostly concentrated in the central charge region,Milestone,Bohr Model,Electrons in atoms orbit the nucleus The electrons can only orbit stably, without radiating, in certain orbits at a certain discrete set of distances from the nucleus Electrons can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequencydetermined by the energy d