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John Dalton proposed an "atomic theory" with solid spherical atoms based on measurable properties of mass in 1803. Not all atoms are spherical and they aren't completely solid, but A for effort.
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In 1897, Thompson discovered electrons!
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Researched radioactivity and in 1898, discovered Radium and Polonium.
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Thompson made a model that the atom was composed of electrons surrounded by a soup of positive charge, he called this model the Plum Pudding Model. you tried
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In 1905, Einstein made the theory of relativity, which laid the basis for the release of atomic energy.
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In 1911, Rutherford discovered that atoms have a small charged nucleus surrounded by empty space and are circled by electrons. This model is called the Rutherford model and it is correct. However, he did not make it clear how the protons and electrons were arranged within the atom. Good job Rutherford!
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In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits.
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Pauli made the Pauli exclusion principle in 1925, which states that no two electrons can exist in the same quantum state.
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Chadwick discovered neutrons in 1932!
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In 1938, Lise Meitner and Otto Frisch discovered nuclear fission. Frisch was later awarded a noble peace prize even though Meitner gave the first theoretical explanation of the fission process.
