Question 1
For large mass number nuclei which are stable, the ratio of protons to neutrons is
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equal to 1
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greater than 1
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less than 1
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unrelated to the stability of nuclei
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almost 2 to 1
Question 2
Heavy nuclei are unstable because
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each nucleon is a separate particle that is not acted on by the nuclear force.
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there are not enough protons present relative to the number of neutrons for the electrical force to be strong enough.
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the nuclear force dominates the Coulomb repulsive force at distances less than 2 fm, but falls off rapidly at greater distances.
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nuclei are stable only when the number of neutrons equals the number of protons.
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nuclei are stable only when the number of protons exceeds the number of neutrons.