Question

How do I start Determining the number of subatomic particles in the nucleus of a radioisotope?

Answer 1

If you are talking about the particle itself, there is nothing special about radioactivity just found number of protons from periodic table then find number of neutrons using mass number

Answer 2

if you talk about the particle formed after radioactive decay, you need nuclear equation for that

Answer 3

Thank you that actual cleared things up! :)