<span>so you know that </span><span>Oxygen. A, number of protons and neutrons=16 and Z, number of protons=8</span>
<span />so...you find the amount of neutrons a-z=n
16-8=n
16-8=8
<span>then for oxygen A number of protons and neutrons,=18,Z,number of neutrons=8</span>
<span>so....18-8=N</span>
<span>18-8=10</span>
<span>so the difference is in the number of there neutrons, and the main reason of them being a isotope.
</span>