Now under positron emission, we're going to say that an unstable nucleus emits a positron particle. The positron particle itself can be seen as an antiparticle of the electron and because of this it symbolized as 0. So it has no mass number. Just like an electron it is an anti electron particle so it's still E but here it's anti because its symbol is positive instead of negative.

Now when a positron and an electron particles collide, so opposites of each other both are annihilated to form 2 gamma rays. Now this occurs in nuclei with excess number of protons, and just like with electron capture, it's going to help to decrease the number of protons in order to increase our number of neutrons. Here under the polytron emission, we're going to say that a proton splits into a neutron and a positron and that's how we're going to limit the number of protons since we have an excess of them and help to increase the number of neutrons.

Here we have cesium 130, cesium 130. It's going to do positive chronic mission. So here is our positron here, Remember your mass numbers have to be the same on both sides. Here we're going to say that this is still 130. The number of protons have to be the same on both sides. So this is 55 on the reactant side. So we need 55 on the product side. One of them is coming from a positron, so we need 54 more. So here we have 54 which would give us Xenon. So here we've just made Xenon 130 by way of positron emission from cesium 130.