Early 19th century - described atoms as solid spheres & said different spheres made up different elements.
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JJ Thomson
1897 - concluded atoms weren't solid spheres. Said atom must contain smaller, negatively charged particles (electrons). New theory - 'plum pudding model' showed atom as ball of positive charge with electrons stuck in it.
2 of 6
Ernest Rutherford
1909 - conducted alpha particle scattering experiments. Fired positively charged alpha particles at thin sheet of gold - nuclear model shows tiny positive nucleus at centre (most mass concentrated here) and a 'cloud' of negative electrons around it.
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Niels Bohr
Nuclear model suggested electrons contained in shells. Eletrons orbit nucleus in fixed shells, each shell a fixed distance from nucleus
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Rutherford & Other Scientists
Experiments showed that nucleus can be divided into smaller particles called protons.
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James Chadwick
Experiments carried out evidence for neutral particles called neutrons.
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Other cards in this set
Card 2
Front
1897 - concluded atoms weren't solid spheres. Said atom must contain smaller, negatively charged particles (electrons). New theory - 'plum pudding model' showed atom as ball of positive charge with electrons stuck in it.
Back
JJ Thomson
Card 3
Front
1909 - conducted alpha particle scattering experiments. Fired positively charged alpha particles at thin sheet of gold - nuclear model shows tiny positive nucleus at centre (most mass concentrated here) and a 'cloud' of negative electrons around it.
Back
Card 4
Front
Nuclear model suggested electrons contained in shells. Eletrons orbit nucleus in fixed shells, each shell a fixed distance from nucleus
Back
Card 5
Front
Experiments showed that nucleus can be divided into smaller particles called protons.
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