What's the difference between them?
Perhaps if you will ask a little bit more elaborate question it will be possible to give a little bit more elaborate answer.
um which ones are more stable? How is one more massive than the other (Do heavy nuclei have more protons or nuetrons)?
No simple rule. In general heavier ones are less stable, but a lot depends on the number of protons and neutrons present. Very heavy ones are all unstable.
They have more of both. Light stable nuclei have about the same number of protons and neutrons, the heavier the stable nucleus, the higher the neutron/proton ratio.
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