Nuclear Reaction: Neutron & Plutonium-239

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
6 replies · 2K views
kirsten_2009
Messages
136
Reaction score
2

Homework Statement


A neutron strikes a Plutonium-239 (239Pu) nucleus and creates Barium-142 (142Ba). What other element is created?

Homework Equations

The Attempt at a Solution



I actually have no idea...could someone just start me off? Thanks!
 
Physics news on Phys.org
Look up plutonium and its proton count and similarly for barium then use your powers of deduction.

Show us your thought process to get your answer.
 
since there is a difference of 38 protons that are "missing" would it be Strontium that is also created?
 
Yes.

Number of nucleons is conserved. You have to have the same number of protons and the same number of neutrons on both sides of the reaction equation. This is not different from balancing chemical reaction (just then you conserve number of atoms and charge, which is actually applying the same conservation principles).
 
Got it! Thank you =)
 
Sorry, one last question. Would it be Strontium-97 since that is the difference between 239 and 142?
 
Yes and no. Yes - you are right about accounting, number of neutrons after the reaction must equal number of neutrons after the reaction. No - reaction was initiated by an additional neutron, so you should take it into account as well, plus, in such reactions free neutrons are produced (and they further break more nuclei, which is why we call it a chain reaction), and these have to be accounted for too.