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9 months ago
Greeks believed that all matter was made of 4 elements. Fire, earth, water, air
John Dalton (English chemist) proposed the atomic theory of matter. In Dalton's theory all matter is made up of indivisible spheres.
Joseph John Thomson discover electrons and its negative charge. Which then led him to discover the positive charge in an atom. He proposed the plum pudding model. In the model that atom is a ball of positive and negatively charged electrons.
Philipp Lenard described atoms as empty spaces filled with fast-moving dynamides.
Ernest Rutherford believed that atoms were mass contained in a small positive nucleus surrounded by negative electrons.
Niels Bohr model of atoms proposed that electrons can travel along certain pathways around the nucleus, called orbits. This model is sometimes called the planetary model.
James Chadwick discovered the neutron.
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