What occurs when a neutron strikes a stable isotope and causes it to become unstable? A. Energy to mass conversion B. None of these
C. Natural radioactive decay
D. Nuclear fission​

Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation.

Explanation:

hope this helps

A

Explanation:

become unstable and split which will add more mass to it I believe but then again if it splits theidI don't know if it adding mass or just keeping the same so either A or B