Question

What type of isotope undergoes radioactive decay?

Answer 1

Answer:

It should be one that has an unstable nucleus

Explanation:

The forces that normally hold the nucleus together sometimes can't do the job, and so the nucleus breaks apart, undergoing nuclear decay. All elements with 84 or more protons are unstable; they eventually undergo decay. Other isotopes with fewer protons in their nucleus are also radioactive.

I hope this helps :p