Question

why does u238 hold extra neutrons when u235 blows up when one hits it

Answer 1

anyone?

Answer 2

Has anyone ever rode in an AmTran bus?

Answer 3

sorry i dont have physics sorry i cant explain.

Answer 4

its not extra neutrons, uranium is most commonly found as 238

which means it is much more stable, im not an expert in molecular energy and structures but i would assume that 235 has much more energy due to a lack of neutrons thus making it more unstable

there's a lot of vocabulary for this, but i dont remember any of it

Answer 5

U238 and U235 have different binding energies -- that is, the energy required to break the nuclei apart are different. U238 is more stable than U235, so its binding energy is higher -- it requires the absorption of high energy neutrons to break apart a U238 nucleus. On the other hand, the binding energy of U235 is much smaller, so the absorption of low energy neutrons is sufficient to cause it to break apart.

The key to nuclear fission is that the neutrons that are released when a nucleus breaks apart are typically low energy particles. It's not that U238 won't break apart if you fire a sufficiently energetic neutron into it -- it's that the neutrons that are subsequently emitted won't break apart the surrounding atoms, so it won't be a chain reaction.