Balancing Nuclear Equations (OCR A Level Physics): Revision Note

Balancing Nuclear Equations

• Nuclear reactions, such as fission and fusion, can be represented using nuclear equations (which are similar to chemical equations in Chemistry)

  For example:

• The above equation represents a fission reaction in which a Uranium nucleus is hit with a neutron and splits into two smaller nuclei – a Strontium nucleus and a Xenon nucleus, releasing two neutrons in the process

• In the above reaction:

  The sum of top (nucleon) numbers on the left-hand side equals the sum of top number on the right-hand side:

235 + 1 = 236 = 90 + 144 + 2 × 1

The same is true for the lower (proton) numbers:

92 + 0 = 92 = 38 + 54 + 2 × 0

• By balancing equations in this way, you can determine, for example, the number of neutrons emitted by a process like this

  Example:

• In the above example, balancing the numbers on the top shows that 3 neutrons must be released in the reaction (i.e. N = 3)