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John Dalton, a British chemist concluded that all elements are made of atoms that are alike.
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A British scientist J.J Thomson discovered the electron which he described as looking like a muffin with berries or raisins scattered through it.
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A Japanese physicst Hanataro Nagaoka proposed a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle.
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A British physicist Ernest Rutherford established that the nucleus was very dense, small, and positively charged. He also made an assumption that the electrons were located outside the nucleus.
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Danish physicist Niels Bohr displayed a model whiich showed electrons moving in particular layers, or shells, rather than randomly.
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A British physicist James Chadwick discovered the neutron, which explained why atoms were heavier than the total mass of their protons and electrons.
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The present modern model is the result of the work down from years ago to now.
