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In 1803, John Dalton created the Atomic Theory. This experiment proves that atoms of different elements combine to form chemical compounds. Atoms can't be created or destroyed; only the arrangement of the atoms can change. -
Thomson understood that atoms generally have a neutral charge. In order to balance the negative charge on the electrons, he hypothesized that there must be a source of positive charge inside the atom. This led Thomson to suggest that atoms could be thought of as negatively charged particles floating in a soup of positively charged ions. -
In May 1911, Ernest Rutherford discovered that atoms have space with using thin sheets of gold and bombarded it with alpha particles that were emitted by radium. What he found was that some atoms also bounced off of the gold foil and bounced back. -
In 1913, Niels Bohr made a theory of the hydrogen atom. He used information form Rutherford's discovery and the discripti9on of the nucleus and he used Max Planck's Quantum theory to create the atom model -
James Chadwick in 1932, discovered the neutron by conducting an experiment using Beryllium and bombarding it with alpha particles through the decay of polonium.