The number of neutrons in a nucleus can be determined by which relation?

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Multiple Choice

The number of neutrons in a nucleus can be determined by which relation?

The number of neutrons is found from the fact that the mass number equals the total count of protons and neutrons in the nucleus. Since mass number A = Z + N, where Z is the number of protons (atomic number) and N is the number of neutrons, solving for neutrons gives N = A − Z. So, subtracting the atomic number from the mass number yields the neutron count. For example, carbon-12 has A = 12 and Z = 6, so N = 12 − 6 = 6 neutrons. Other options don’t fit because adding mass number and atomic number would not represent a nucleon count, and using atomic weight (a weighted average) with mass number isn’t the direct, exact relationship for a specific nucleus.

The number of neutrons is found from the fact that the mass number equals the total count of protons and neutrons in the nucleus. Since mass number A = Z + N, where Z is the number of protons (atomic number) and N is the number of neutrons, solving for neutrons gives N = A − Z. So, subtracting the atomic number from the mass number yields the neutron count.

For example, carbon-12 has A = 12 and Z = 6, so N = 12 − 6 = 6 neutrons.

Other options don’t fit because adding mass number and atomic number would not represent a nucleon count, and using atomic weight (a weighted average) with mass number isn’t the direct, exact relationship for a specific nucleus.

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