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Democritus said that matter consists of really small, indivisible particles; Atoms.
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All matter is made of atoms, which are indivisible and indestructible.
All atoms of a given element are identical.
Compounds are formed by a combination of two or more different kinds of atoms.
A chemical reaction is a rearrangement of atoms. -
JJ Invented the ‘Plum Pudding’ model - atoms have a positive sphere (pudding) with negative electrons (plums) dispersed throughout.
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Ernest discovered nucleus of atoms. Invented the ‘nuclear’ model - atoms hava a dense positive nucleus surrounded by negative electrons.
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Niels invented the ‘Planetary’ model - atoms have electrons that move in circular orbits within specific energy levels.
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Revised ‘Nuclear’ model – atoms have a neutral particle in the nucleus (neutrons).