Of the two isotopes of iodine, 196Pb and 206Pb, one is nonra-dioactive and one decays by positron emission. Which does which? Explain.

Video transcript

Hello everyone today we are being asked the following question, consider two isotopes of platinum, platinum 1 88 and platinum 1 95 which nuclei is not radioactive. In other words, this question is asking us which is the stable nuclei and sort of find the stability, We have to find first what the atomic number of platinum is. If you go on the periodic table, we see that the atomic number which is also equal to Z is 78. With this. If an atomic number is greater than 76, we can say that it is stable at a neutron to proton ratio Of 1.5. So what we're gonna do is we're gonna take each of these isotopes and we're going to find the ratio. So first we'll start with our platinum 188. We're going to have our ratio here and to find the neutrons, we simply take the atomic mass which was 1 88. It was subtracted by the number of protons, which is equal to the atomic number which was 78. And then of course we divide by atomic number and this gives us 1.41 and this is less than 1.5. So this is ultimately going to undergo electron capture Next. We'll try our platinum 195. So we have our ratio here. As usual, we're gonna do our mass - Our atomic number divided by the atomic number. We're going to find this is actually going to equal 1.5 and as we said before, a ratio that's equal to 1.5 is going to be stable. So the nuclear that is not radioactive or in other words, is stable, is going to be our platinum 1 95. And with that, we've answered the question overall, I hope this helped, and until next time.