What happened around 430 BC to do with the model of the atom?
First mention of an atom by Greek Philosophers. They suggested there was a limit to how many times a rock could be split in half and that the smallest piece that could be split no further was called an atomos
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What does atomos mean?
Indivisible (uncuttable)
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Who discovered the electron?
JJ. Thompson
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When was the electron discovered?
1897
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What did Thompson suggest?
The atom was like a plum pudding (Christmas pudding) with the raisins in the pudding representing the negative electrons embedded in a sphere of positive charge
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Who undertook the Rutherford experiment?
Hans Geiger, Ernest Mardsen
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When was the Rutherford experiment undertaken?
1909
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What were the details of the Rutherford experiment?
Particles called 'Alpha' were fired through a vacuum at a very thin gold leaf (10 atoms thick). Alpha particles were known to be very small and positively charged
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What were the results of the Rutherford experiment?
Most alpha particles went straight through or were deflected very slightly as expected from the plum, pudding model. However around 1 in 8000 were deflected by more than 90 degrees n(backscattered)
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What were the results of the rutherford experiment?
The atom must have a nucleus which is very dense, small and highly positively charged. The rest of the atom is almost entirely space
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In what year was the Rutherford solar system model made?
1911
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What is the charge of electrons?
-1
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What is the charge of neutrons?
0
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What is the charge of protons?
+1
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What did Neil Bohr realise?
Quantum physics meant that electrons could only be found in very distinct energy lkevels around the atoms called shells and that trying to pinpoint exactly where they were within that shell at any time was impossible
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