Atom Timeline by Ellie Chabot https://padlet.com/chabote19/atomtimeline en-us 2016-09-18 20:04:47 UTC 2026-03-21 14:49:05 UTC hello@padlet.com 422 BC - Democritus - Atomos chabote19 https://padlet.com/chabote19/atomtimeline/wish/124589114      Democritus discovered that all matter is composed of indivisible particles called atoms and a void (empty space) with Leucippus.
     He figured that if he kept cutting a stone that every piece would have the same properties as the original stone until you couldn't cut the stone into any more pieces. 
Solid but differ in size, shape, mass, position and arrangement with a between them. 
]]> 2016-09-18 20:50:32 UTC https://padlet.com/chabote19/atomtimeline/wish/124589114 1803 - John Dalton - "Billard Ball" Model chabote19 https://padlet.com/chabote19/atomtimeline/wish/124589926      John Dalton discovered that atoms of the same element are identical in size and mass and atoms can't be subdivided, created or destroyed.
     He used patterns in the circles to distinguish different elements so he could symbolize individual atoms to combine others together.
Atoms are spherical and are moving like a billiard ball.]]> 2016-09-18 21:04:22 UTC https://padlet.com/chabote19/atomtimeline/wish/124589926 1897 - J.J. Thomson - "Plum Pudding" Model chabote19 https://padlet.com/chabote19/atomtimeline/wish/124591547      J.J. Thomson discovered the electron and that it must be negative, so matter must be positive.
     He used properties of a cathode ray, which separated atoms and molecules by using positive rays.
Atoms where spheres filled with a positively charged liquid and scattered in the liquid were electrons. ]]> 2016-09-18 21:29:30 UTC https://padlet.com/chabote19/atomtimeline/wish/124591547 1911 - Ernest Rutherford - Nuclear Model chabote19 https://padlet.com/chabote19/atomtimeline/wish/124593194      Ernest Rutherford discovered the nucleus and that electrons orbited the nucleus with empty space between both.
      He used a gold foil experiment, shooting alpha atoms at the foil, to discover the nucleus.
A positive center was surrounded by orbiting negative electrons and empty space. ]]> 2016-09-18 21:55:12 UTC https://padlet.com/chabote19/atomtimeline/wish/124593194 1913 - Niels Bohr - Bohr Model chabote19 https://padlet.com/chabote19/atomtimeline/wish/124595288      Niels Bohr discovered energy levels or electron shells, which are certain distances from the nucleus where electrons orbit and the Planck quantum theory which explains how electrons can jump energy levels.
     He used a light and glass prism, where he noticed that at different levels certain colors can be seen.
The positive nucleus surrounded by different energy levels that electrons orbit in, like the sun and all the planets. 
]]> 2016-09-18 22:29:55 UTC https://padlet.com/chabote19/atomtimeline/wish/124595288 1926 - Erwin Schrödinger - Electron Cloud Model chabote19 https://padlet.com/chabote19/atomtimeline/wish/124596436 Erwin Schrödinger discovered that electrons do not travel in set paths and the Schrödinger equation which describes how the quantum state of a system changes with time.
He used Bohr's model to help him create equations to find an electron in a certain position.
Nucleus in the center with electrons moving around it anywhere they want with empty space in between]]> 2016-09-18 22:50:23 UTC https://padlet.com/chabote19/atomtimeline/wish/124596436