https://padlet.com/lihubschman/9394jing3k4mwayt Atomic Theory en-us 2020-12-04 14:54:07 UTC 2024-06-05 23:51:01 UTC hello@padlet.com lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987739115 Democritus was an ancient Greek philosopher. He wondered how many times matter could be divided until her found the smallest piece. He believed the smallest piece was indivisible. He names this piece "atomos" which is Greek for indivisible. He made his contribution in 400 B.C.]]> 2020-12-04 14:55:42 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987739115 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987739945 Aristotle was also a Greek philosopher. He believed that all matter was made up of air, fire, earth, and water. He made his theory in 300 B.C. and it was believed until the early 1800's. ]]> 2020-12-04 14:55:54 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987739945 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987754648 In 1803, John Dalton, an English chemist, ran a number of experiments to confirm the idea of atoms. He theorized that each atom is a certain element and atoms of the same element are exactly alike. Additionally, atoms of different elements are different and they can  combine with other elements to form compounds. ]]> 2020-12-04 14:59:15 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/987754648 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991600374 In 1897, J.J. Thomson gave ideas about atoms having smaller particles inside them. Thomson discovered small negatively charged particles, electrons. He then made the "Plum Pudding" model. He believed atoms are made from a substance which is positively charged. In that substance, there are negatively charged electrons scattered around. ]]> 2020-12-06 14:30:43 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991600374 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991620345 In 1908-1911, Rutherford performed an experiment in which he fired positively charged particles at a gold foil. Through this experiment, he discovered that atoms have a small, dense, positively charged center, which he called the nucleus. He also discovered that the nucleus is much smaller than the atom itself because an atom is made up of mostly empty space. Finally, he concluded that electrons are scattered around the nucleus at a distance. ]]> 2020-12-06 14:45:11 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991620345 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991621766 In 1913, Bohr improved the atomic model. He discovered that electrons move in an orbit around the nucleus. The orbits or energy levels, are located at a certain distance from the nucleus and the location of an  electron  depends on how much energy it has. ]]> 2020-12-06 14:46:18 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991621766 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991671578 In 1932 Chadwick discovered that there are neutrally charged particles in an atom. These ended up becoming neutrons. He also confirmed the theory that most of an atoms mass is in the nucleus. ]]> 2020-12-06 15:22:15 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991671578 lihubschman https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991674828 In the 20th century, scientist like Heisenberg, Eisenstein, and many others finalized the atomic theory that we use today. In today's atomic theory, electrons move in high speeds around the nucleus in clouds instead of orbits. In the electron cloud, electrons whirl around the nucleus billions of times in one second. ]]> 2020-12-06 15:24:17 UTC https://padlet.com/lihubschman/9394jing3k4mwayt/wish/991674828