https://padlet.com/klee0808/a0cyh99ept8s By Koby Lee en-us 2019-05-27 01:12:40 UTC 2019-05-30 00:15:25 UTC hello@padlet.com https://imgglb.padletcdn.com/v13/image?t=g_auto&url=https%3A%2F%2Fpadlet.net%2Ficons%2Fpng%2F1f52c.png klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363620275 Leucippus and his pupil Democritus first came up with the idea that matter is composed of tiny particles. The idea came from the thought that if you indefinitely kept slicing something in half, there would eventually be a particle that couldn't get smaller.]]> 2019-05-27 01:16:37 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363620275 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363770374 Antoine Lavoisier developed the Law of Conservation of Mass. This law stated that even if matter changes shape or form, its mass stays the same.]]> 2019-05-27 14:54:29 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363770374 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363771056 John Dalton determined that elements exist as discrete packets of matter ]]> 2019-05-27 14:57:57 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363771056 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363772079 Scientists start experimenting with discharge tubes, which emit light when an electrical current passes through them. The scientists realized the light wasn't just being emitted from the negative electrode, but the positive electrode as well. This proved there must be positive charge in matter.]]> 2019-05-27 15:02:48 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363772079 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363773203 J.J. Thompson discovers the electron. Thompson calculated the mass of cathode rays and concluded that since the mass was one thousand times lighter than hydrogen, then cathode rays weren't rays, but rather negatively charged particles.]]> 2019-05-27 15:09:24 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363773203 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363774120 Thompson creates the Plum Pudding Model of the atom which has the negatively charged electrons distributed randomly in a positively charged matrix.]]> 2019-05-27 15:14:53 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363774120 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363774622 Earnest Rutherford does his gold foil experiment.]]> 2019-05-27 15:17:23 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363774622 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363775395 Rutherford concludes from his gold foil experiment that atoms have a nucleus filled with tiny positive ions (protons) and that most of the atom is empty space.]]> 2019-05-27 15:21:36 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363775395 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/363775970 Niels Bohr comes up with the Bohr Model of the atom which represents the electrons in orbits around a small central nucleus. Each orbit can have a specific number of electrons which correlates to the energy levels and orbitals in the modern model of an atom.]]> 2019-05-27 15:25:03 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/363775970 klee0808 https://padlet.com/klee0808/a0cyh99ept8s/wish/364198750 Werner Heisenberg publishes his breakthrough paper of quantum mechanics. In it, he states it is impossible to know with certainty both the momentum of any subatomic particle and its exact position. From this, he concludes electrons aren't particles or waves, but that they have properties of both and neither. So he creates the quantum model of the atom with clouds representing the probability of finding an electron in any particular position.]]> 2019-05-29 01:13:51 UTC https://padlet.com/klee0808/a0cyh99ept8s/wish/364198750