Chemistry - Changing ideas of atoms

Changing ideas (theories)

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When did explanation of atoms begin?
400BC
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Put J.J. Thomson, Niels Bohr, James Chadwick, John Dalton, Geiger + Marsden, Democritus and Ernest Rutherford in order of the discovery of atomic structure.
Democritus --> John Daltion --> J.J Thomson --> Geiger and Marsden --> Ernest Rutherford --> Niels Bohr --> James Chadwick
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What did Democritus do and when?
In 400BC, he introduced th idea of materials being made of small particles which couldn't be divided. He had no evidence.
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What did John Dalton do and when?
In 1803, Dalton described the atom as a billiard ball which could not be divided
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What did J.J. Thomson do and when
In 1847, Thomson discovered the electron. He created the plum-pudding model. He said that megative electrons were embedded into a ball of positive charge
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What did Geiger and Marsden do?
In 1909, they held an experiment whihc involved firing alpha particles at a gold foil. The particles reflected in multiple different directions which wasn't expected. This proposed the idea of the atom having a nucleus.
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What did Ernest Rutherford do and when?
He suggested that the atom had a positively charged nucleus where most of the mass was concentrated. He created the nuclear model.
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What did Niels Bohr do and when?
In 1913, he used theoretical calculations to explain that the electrons orbited the nucleus in definite orbits. He said a fixed amount of energy is needed for an electron to move from one orbit to the next.
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What did James Chadwick do and when?
In 1932, James Chadwick discovered the neutron
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Card 2

Front

Put J.J. Thomson, Niels Bohr, James Chadwick, John Dalton, Geiger + Marsden, Democritus and Ernest Rutherford in order of the discovery of atomic structure.

Back

Democritus --> John Daltion --> J.J Thomson --> Geiger and Marsden --> Ernest Rutherford --> Niels Bohr --> James Chadwick

Card 3

Front

What did Democritus do and when?

Back

Preview of the front of card 3

Card 4

Front

What did John Dalton do and when?

Back

Preview of the front of card 4

Card 5

Front

What did J.J. Thomson do and when

Back

Preview of the front of card 5
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