Page 502 - Chemistry eBook

Fission
FISSION: One atom splits into two or more smaller pieces and gives off energy
• The atom is bombarded by a neutron, which makes the nucleus unstable. So the atom splits into smaller pieces.
• The neutrons given off bombard other atoms, which make them split into smaller pieces.
• If this process keeps repeating uncontrollably, BOOM – it creates an atom bomb!
• When the atom splits, some mass turns into energy. Therefore, the original atom’s mass is bigger than the sum of the smaller pieces – because some of the mass
got converted into energy.
235U + 1n 236U 141Kr + 92Ba + 3 1n + energy 0 56 36 0
235U is bombarded by a neuron, which turns the element into 236U (because mass was added with the neutron).
Then, 236U breaks down into smaller pieces (141Kr and 92Ba), 3 neutrons, and energy.
There are many Regents questions on fission.
You must recognize this example.
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501 © UNIT 12: NUCLEAR CHEMISTRY