Confused about isotopes and what makes them unstable/stableWatch
Can I change the number of neutrons of an element to any number for it to become an isotope?
How do I know what isotopes are radioactive? What makes an isotope stable even??
Isotopes that have a very unstable nuclei due to the unbalance of the number of neutrons and protons achieve stability by shedding particles and energy, and in the process, becoming radioactive.
As for determining the stability of the isotope, this website explains everything in great detail. Do give it a read.