Suggest — 4 marks
In 1909, Ernest Rutherford's team conducted the famous gold foil experiment. They fired alpha particles at a thin sheet of gold foil and observed how the particles were deflected. Most alpha particles passed straight through with little deflection, but some were deflected at large angles, and a few even bounced backwards. This experiment provided crucial evidence that challenged the existing 'plum pudding' model of the atom.
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Suggest why most alpha particles passed straight through the gold foil with little or no deflection.
[1 mark]
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Suggest why some alpha particles were deflected at large angles or bounced backwards.
[2 marks]
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Suggest how Rutherford's observations from this experiment led to the development of the nuclear model of the atom, rather than supporting the plum pudding model.
[1 mark]
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Calculate — 4 marks
A scientist is studying the structure of atoms using experimental data. She observes that an atom of carbon has 6 protons in its nucleus. She needs to determine information about the atomic structure and compare it with another element.
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A carbon atom has a mass number of 12 and an atomic number of 6. Calculate the number of neutrons in a carbon atom.
[1 mark]
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An oxygen atom has an atomic number of 8 and a mass number of 16. Calculate the number of neutrons in an oxygen atom.
[1 mark]
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Calculate the total number of electrons in 2 carbon atoms (atomic number 6). Assume the atoms are neutral.
[2 marks]
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Evaluate — 3 marks
Scientists in the early 20th century debated the structure of the atom. Rutherford's nuclear model (1911) replaced Thomson's plum pudding model after the gold foil experiment. However, Rutherford's model had a significant theoretical problem: according to classical physics, electrons orbiting the nucleus should continuously emit electromagnetic radiation, lose energy, and spiral into the nucleus in a fraction of a second. This prediction contradicted experimental observations that atoms are stable.
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Identify one piece of experimental evidence from the gold foil experiment that contradicted Thomson's plum pudding model.
[1 mark]
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Evaluate how effective Rutherford's nuclear model was at explaining atomic structure, considering both its strengths and limitations.
[2 marks]
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Explain — 3 marks
Scientists have used different experimental techniques to understand atomic structure. In the early 1900s, Ernest Rutherford conducted the famous gold foil experiment where alpha particles were fired at thin gold foil. Most particles passed straight through, but some were deflected at large angles, and a few bounced straight back. This experiment was crucial in developing our modern model of the atom.
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Explain why Rutherford's results contradicted the plum pudding model of the atom.
[1 mark]
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Explain how Rutherford's observations of alpha particles bouncing back from the gold foil led to the conclusion that most of the atom's mass is concentrated in a small nucleus.
[2 marks]
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Describe — 5 marks
Scientists in the early 20th century used alpha particle scattering experiments to investigate the structure of atoms. Ernest Rutherford's team fired alpha particles at a thin gold foil and observed how the particles were deflected. This experiment led to significant changes in our understanding of atomic structure.
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Describe how the results of the alpha particle scattering experiment contradicted the plum pudding model of the atom.
[2 marks]
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Describe the nuclear model of the atom that Rutherford proposed based on the scattering results.
[2 marks]
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Describe one limitation of Rutherford's nuclear model that was later addressed by the Bohr model of the atom.
[1 mark]
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GCSE Perfect