13.1 Chain Reaction Theory
If you are familiar with the periodic table of elements, you will know that the elements in the table are listed in the order of the number of protons in their nucleus. So the first element is hydrogen whose nucleus contains 1 proton and the last element of the naturally occurring elements is uranium which contains 92 protons.
As well as containing protons, the nucleus also contains neutrons. However, in the case of neutrons, the nucleus can contain a varying number. This is what gives rise to the existence of “isotopes.” The heavier elements contain more neutrons than ...
