成果大物二-ii課件atomic structure

1、ATOMIC STRUCTURES.MORRIS 2006HISTORY OF THE ATOM460 BCDemocritus develops the idea of atomshe pounded up materials in his pestle and mortar until he had reduced them to smaller and smaller particles which he calledATOMA (greek for indivisible)1808John Daltonsuggested that all matter was made up of t

2、iny spheres that were able to bounce around with perfect elasticity and called themATOMS 1898Joseph John Thompsonfound that atoms could sometimes eject a far smaller negative particle which he called anELECTRON Thompson develops the idea that an atom was made up of electrons scattered unevenly withi

3、n an elastic sphere surrounded by a soup of positive charge to balance the electrons charge Like plums surrounded by pudding.1904PLUM PUDDINGMODEL1910Ernest Rutherfordoversaw Geiger and Marsden carrying out his famous experiment. they fired Helium nuclei at a piece of gold foil which was only a few

4、atoms thick.gold foilhelium nucleiThey found that while most of the helium nuclei passed through the foil, a small number were deflected and, to their surprise, some helium nuclei bounced straight back like a tennis ball hitting a wall .helium nucleiIn 1911, Rutherford proposed a revolutionary view of the atom. He suggested that the atom consisted of a small, dense core of positively charged particles in the center (or nucleus) of the atom, surrounded by a sw