Changes

[[John Dalton]] developed a realistic atomic theory based on four principles:  that all matter is composed of atoms, that each element's atoms are of one size, atoms combine chemically to form compounds, and chemical reactions occur when atoms are joined or separated.  His theory relied on [[Antoine Lavoisier|Lavoisier's]] [[Law of the conservation of mass|Law of Conservation of Mass]] and Joseph Proust's [[Law of definite proportions|Law of Definite Proportions]].

[[John Dalton]] developed a realistic atomic theory based on four principles:  that all matter is composed of atoms, that each element's atoms are of one size, atoms combine chemically to form compounds, and chemical reactions occur when atoms are joined or separated.  His theory relied on [[Antoine Lavoisier|Lavoisier's]] [[Law of the conservation of mass|Law of Conservation of Mass]] and Joseph Proust's [[Law of definite proportions|Law of Definite Proportions]].

J. J. Thompson later developed the [[Plum Pudding]] Model, a result of his discovering the [[electron]] using [[cathode ray tube]].  [[Ernest Rutherford]] later discovered in his [[Geiger-Marsden experiment|gold foil experiment]] that the atom was mostly empty space, with a nucleus of protons in the center.  James Chadwick discovered the neutron and complexities of the nucleus, paving the way for [[nuclear fission]].

J. J. Thompson later developed the [[Plum Pudding]] Model, a result of his discovering the [[electron]] using [[cathode ray tube]].  [[Ernest Rutherford]] later discovered in his [[Geiger–Marsden experiment|gold foil experiment]] that the atom was mostly empty space, with a nucleus of protons in the center.  James Chadwick discovered the neutron and complexities of the nucleus, paving the way for [[nuclear fission]].

==See also==

==See also==

*[[Element]]

*[[Element]]