How is nuclear stabilty related to the neutrons-protons ratio?

The nucleus is unstable if the neutron-proton ratio is less than 1:1 or greater than 1.5.

At close distances, a strong nuclear force exists between nucleons.This attractive force comes from the neutrons.

More protons in the nucleus need more neutrons to bind the nucleus together.

If the neutron-proton ratio is 1:1, the nucleus is stable. However, it is unstable if the ratio becomes less than 1:1.

The nucleus is stable if the neutron-proton ratio is 1:1 and unstable if less than 1:1 or greater than 1.5.

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The nucleus is unstable if the neutron-proton ratio is less than 1:1 or greater than 1.5.