Which would result in radioactive decay? Check all that apply.

Large nuclei need more neutrons than protons to help hold them together, so a neutron-to-proton ratio of 1:2 is unstable. A nucleus with 90 protons and 100 neutrons also has too few neutrons for such a large nucleus and will decay. Every uranium isotope is radioactive. By contrast, a small 1:1 nucleus and oxygen-16 (8 protons and 8 neutrons) can be stable, and potassium has stable isotopes, so not every potassium isotope decays.

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