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John Dalton proposed the first atomic theory
His theory had 4 statements;
1. Atoms are tiny, invisible particles.
2. Atoms of one element are all the same.
3. Atoms of different elements are different.
4. Compounds form by combining atoms -
J.J. Thomsom discovered the electron
Thomsom discovered particles with a positive charge. His model was known as "the raisin bun model". -
Ernest Rutherford discovers the nucleus and protons
He named the nucleus and protons. -
Niels Bohr improved Rutherford's model
He proposed that electrons move around the nucleus