ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ° ÜÛÛÛÛÛÛÛÜܲßßßÛÛÛÛÛÛÛÛ°ÛÛÛÛ Ü  ܲ ÞÛ °Hello, and welcome toÛÛÛÛÛ Ü²²ÜܲßÜÞ² Û Jason Matsumoto's project onÛÝÜ°Û²ßܰܰܲßÜ±ß²ß  Ûthe atomic model for Mrs. Lau'sÝÞ°²Û °ß°°Ü Üßßܲ Üß  Þblock HÛÛChemistry 11IB class!Û ß° ÜÛ±ßܲÜÜÜÜþß±  ßÛÛÛÛÛ þܲÜÜÛÛÛÛÛÛÛÛÛÛÛÜÜÛÛ°°ß Þ²ÜÝÞÛß²²±Ý  ßßßßßßßßßßßßßßßßßÛßß²ßßß  ÜÜßܲÜßÛß°ßÜÜ ßßß²ÛÜÜÜÜ Þ²²ÛÜÜܲÜÜÜ±ß°Ý   ß²ÛÛ²ßßßßÜÜ°ß   ßßßßßßß ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÜßÜÜßÜÜÛ I suppose you're wonderingÛÛÛÜ ²ÜÜÛ²Üß°ÛÜÞÛhow the atomic model all began.ÛÝ Þ²Û²ß²ÝÞܲÝßÛß²Ü Well, I'll tell you.ÛÛÛ°°Ûß Üß°ßÛßÜÜÜßÜ ßßÛ²ßßßßßßßßßßßßßßßßßßßßßßß Þ°°ÜÜܲÜßܲ²Ýßßß ß°ÜßßßßÛÛ°ß ßßßßß  In around 330 B.C., a Greek philosopher named Democritus claimed that all  matter is composed of tiny particles. He called these particles "atoms", which means "unbreakable", because that's what he thought: that they were unbreakable.  However, another Greek philospher, Aristotle, refused to accept this  theory, and it was ignored by everyone for centuries. Then, in 1807, an Englishman named John Dalton developped the first "real" atomic model. He concluded through chemical evidence that atoms were indivisible particles, uniformly dense, and spherical in shape.   ÛßßßßßßßßßßßßßßßßßßßßÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÛÜÜÛÜÜÛÛÛÜÜÛßßÛ1807- Dalton's model.Û ÛÜܲÛßßßÛÛÛÛÛÛÜÛÛ It can be compared Û ÛÞÛÜßÛÛÛÛÛÛÛÛÛÛÛÝ ÛÛto the structure ofÛ ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛa billiard ball.Û ÛÞÛÛÛÛÛÛÛÛÛÛÛÛÜÛÝÛßßßßßßßßßßßßßßßßßßßßßßß ÛßÛÛÛÛÛÛÛÛÜܲßßÛ ÛßßÛÛÛÛßßßßÛ ÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÛ ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÜÛÛÜܲßßßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ°°ÛÛÛ°°ÛÜ ÞÛÛDalton's theory that atoms wereÛÛÝ  þßܲßßÛindivisible was challenged roughly ° ÜܲÛÜßß²ÜÛÛÛ100 years later by a man named Û°° Þ²ÛÛß²ÝÞ±ÜÝÞÛÛÛÛÛÛÛJoseph John Thomson.ÛܲÜþÛÛÛÝ  ÜÜß°ÛÛßÜÜßßÜßßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛßßßßÛÛÛÛßß  Þ²²±ÜÜܲÛÛ ²±ÝÜÜ°ßß  ß±°°ÜßßßßÛ²ßßßßßß  ßßßßßß In 1903, another English scientist, J. J. Thomson, devised a newatomic model, the first to claim that the atom was composed of even smaller  particles: electrons, which carried negative charges, and protons, which carried positive charges. He saw the atom as a chunk of positive charge, with electrons scattered about to neutralize the charges. This model is often called the "plum pudding model", as it resembles it in structure. This was the first time the electronic nature of the atom was recognized. ÛßßßßßßßßßßßßßßßßßßßßÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÛÜÜÛÜp+Ûe-ÜÛßßÛ1903- Thomson's model.Û ÛÜܲÛßßßÛÛÛÛp+ÜÛÛ It can be compared  Û ÛÞÛÜßÛÛe-ÛÛÛÛe-ÛÝ ÛÛto the structure of Û ÛÛe-ÛÛÛÛÛp+ÛÛÛÛÛÛÛÛplum pudding.  Û ÛÞp+ÛÛÛÛÛÛe-ÛÛp+ÝÛßßßßßßßßßßßßßßßßßßßßßßßß ÛßÛÛÛp+ÛÛÛÜܲßßÛ ÛßßÛe-ÛßßßßÛ ÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÛ ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÜÛÜܲßßßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ°°°ßßÛÛÛÛÛ ß²ÛÜ Þþß ÛThomson discovered the existance ofÛÛÛÛÛÝ ÛÛelectrons and protons through experimentsÛÛÛ ÜÜ ÜÜ ÞÛÛÛÛÛÛinvolving cathode-ray tubes.ÛÛÛÛܲÜþÛÛÝ  Üßþ°Ý ܲÜÞÝ ßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ°°ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛßßßÛÛÛÛßÜÛ²ßܲܰÜß ßßßßßßßÛ±ßßßßßßßßßßßßßßßßßßßßßßß°ÛÛßßß Þß²ÝÞ²ßÛÛ°Ý ÛÛßßßßÜÜÜÜþßÜÜßßÜÜßÛ²ßßÜÜßßþ ÛÛ ÜÜÜ ÜܲÜÜÜ°ßÝÜÜ ÜÜÛÛÛÛ²ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ°ÛÛÛÛÛÛÛÛÛÛÜÜ  ß° ß²°°ÛÜÜÜ°°ßß ÜÜßÛÛAs cathode-rays (low pressure gas)Ûß²ÜÛÜ  ÞÞ²ÛÛwereÛcharged with electricity whileÛÛÛÞÝÛÝ ÛßÛÛpassing alongÛthe tube, they would bendÛÛÛÛ  ÞÛÛhen encounteringÛmagnets. This meant thatÛÝ  ßÛÛÛÛÜܱthe gas hadÛcharged particles.ÛÛÛÛÛÛß  ßßÛÛßßßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛßß  In 1911, Ernest Rutherford developped yet another atomicmodel after he found a fault in Thomson's previous model. In an experiment, he bombarded  a sheet of metal foil with alpha particles, with a fluorescent screen   surrounding the area to observe where the alpha particles would end up. To his amazement, some of the alpha particles would deflect at a very wide angle, contrary to his belief that most would either go straight through or have a very small change in direction.He concluded that Thomson's modelwasnotentirely correct, and that the atoms actually had a dense nucleuscomposedof protons, whichdeflected thealpha particles if hit  head-on. He thendevelopped an idea on the positioning of electrons:  hovering around thepositively charged nucleus. ÛßßßßßßßßßßßßßßßßßßßßÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÛÜÜßße-ßßßÜÛßßÛ1911- Rutherford's modelÛ ÛÜß ßÜÛÛ It can be compared to Û ÛÞÝ ÞÝ ÛÛplanets, orbitting  Û ÛÛ p+p+ ÛÛÛthe sun in the middle.Û ÛÞÝ p+ Þe-Ûßßßßßßßßßßßßßßßßßßßßßßßßßß Ûe- ÜßÛ ÜÜÛÛÛÛÛÛÛßßßß²ÜÜÜ°°ÛÛÛÛÛÛÜÜ ÛßßÜÜÜÜÜÜßßÛ ܲÛÛÛNiels Bohr, in°1913,ÛÛÛÛÛÜ ÛÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÛ ÞÛwould later use the quantum°°ÛÝ  ÛÛtheory to explain how theÛÛÛÛÛÛ  ÜÜÛÛÜßß²Ü ÞÛ°°electrons orbitÛwithoutÛ ÜþÛÝ  Þ±²²ß²ÝÞ°ßÝ ßÛÛÛÛÛgenerating energy.ÛÛÛß²Ûß  Üß°Û²ßÜÜßßÜÛÜ ßßß²ÜÜÜÜÜÛÛÛÛÛ²ÛÛÛÛÛÛÛÛÛÛßß  Þß²ÜÜÜÛÛÛÛÛÛÛ²ÝÜÜܲßß ÜÝÛ°ÜÜßßßßÛÛÛ²²ßßßßßß ²²Þ°±±°Û°Û²ß Ü Þ²ÝÞ±±²±°±°Ýßßß²Ûß ßß²²²±±°ÛÜ ßß²°°°ÛÜÜ ßß°Û²ÛÜ Ü²Ûß ßÜܲ±ß ßß°ßÜ  In 1932, it was discovered that there was another subatomic particle, this  time without a charge. It was a British scientist, James Chadwick, who discovered this after finding particles similar to protons in mass which failed to react to electric or magnetic fields. It was called the  neutron, and it was found to be with the proton, in the nucleus. So, the accepted model today is basically the Rutherford model, except we now include neutrons in the nucleus. SAUCE00The Atomic Model (grade: 32/40) Nitnatsnoc ACiD 19951107V,PŒ