For light atoms, what neutron-to-proton ratio is typical for stability?

For light atoms, what neutron-to-proton ratio is typical for stability?

• A. 1 to 1.
• B. 1.5 to 1.
• C. 0.5 to 1.
• D. 2 to 1.

Answer: (A)

For light nuclei, stability occurs when the numbers of neutrons and protons are roughly equal. Neutrons contribute to binding via the strong force without adding electric repulsion, so in light elements the balance is around one neutron for every proton. That 1:1 ratio gives stable isotopes like carbon-12 (6 protons and 6 neutrons) and oxygen-16 (8 and 8), illustrating why the neutron-to-proton ratio near 1 is typical for stability in light atoms. Choosing a significantly higher neutron-to-proton ratio would imply extra neutrons without a corresponding need for them in the light region, and a lower ratio would leave the nucleus less bound due to insufficient neutrons to offset proton-proton repulsion, making those configurations unstable for light elements.

For light nuclei, stability occurs when the numbers of neutrons and protons are roughly equal. Neutrons contribute to binding via the strong force without adding electric repulsion, so in light elements the balance is around one neutron for every proton. That 1:1 ratio gives stable isotopes like carbon-12 (6 protons and 6 neutrons) and oxygen-16 (8 and 8), illustrating why the neutron-to-proton ratio near 1 is typical for stability in light atoms.

Choosing a significantly higher neutron-to-proton ratio would imply extra neutrons without a corresponding need for them in the light region, and a lower ratio would leave the nucleus less bound due to insufficient neutrons to offset proton-proton repulsion, making those configurations unstable for light elements.