Atomic Timeline
Category: Other
Updated: 10 Sep 2017
Contributors
Created byAlicia Liew
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Events
Democritus :
- It was the first atomic model, he said that all matter is made up of atoms, which are invisible particles that cannot be destroyed.Aristotle :
He didn’t believe in atomic theory. He thought that all materials on earth were made of four elements, Fire, Earth, Water and Air, and not made up of atoms. Moreover, he believed that the Earth was the centre of the Universe.John Dalton :
He had Ancient Greek ideas of atoms, he said that elements consisted tiny particles which are atoms.J.J. Thomson :
His atomic model was called the 'Plum pudding'.He discovered about the electrons and he even noticed that an atom can be divided. He also said that aoms are made of positive cores and negatively charged particles within it.Ernest Rutherford :
He disproved the plum pudding because he discovered that the only “solid" part of the atom is the atomic nucleus. In addition, he discovered that the nucleus of certain elements could be “disintegrated” by the impact of energetic alpha particles coming from some radioactive source.Niels Bohr :
He said that the nucleus lies in the centre of the model and is made up of a certain number of protons and neutrons. Also,for each of the outer layers are made up of a certain amount of electrons.Louis de Broglie :
He discovered the wave mechanics theory. He believed that electrons can act like both particles and waves, just like light and then he discovered that electrons can act like waves. Moreover, the waves produced by the electrons contained in the orbit around the nucleusMurray Gell-Mann :
He showed what makes up protons and neutrons.
He discovered the quark, a fast moving point of energy and said that for every proton and neutron contains three quarks.Werner Heisenberg :
He calculated the behaviour of electrons. In addition, he also found the Uncertainty Principle, which says that electrons do not travel in neat orbits and surrounding the outside of the nucleus is an electron cloud, the name given to the electrons that are widely spreading and moving around.
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