Why do we use uranium and plutonium for nuclear weapons and reactions?

Question

I would think that neutrons can break up any nucleus apart. Why not just use aluminium or iron. Is it because of E=mc^2 ? Greater mass equals greater energy? Would a bomb made of another material be less radioactive?
TIA

In: 30

Answer 1

Some atoms are less stable! The bigger the atom, the harder it is (generally) to hold all those neutrons and protons together, meaning it won’t take as much energy to blast them apart.