Of the two isotopes of iodine, 136I and 122I, one decays by b emission and one decays by positron emission. Which does which? Explain.

Video transcript

Hello everyone today. We have the following question. Consider two isotopes of bromine, bromine 71 and bromine 86, which nuclei undergoes positron emission. So the first thing you want to make note of is the atomic number of browning, which is equal to Z. And this is going to be 35 and this is per the periodic table. Another thing we must make note that if an atomic number is between and 40 or equaling 40 then the ratio of neutrons to protons is stable, treasure At 1.25. And so that's what we're gonna do here. We're gonna calculate the NZ ratio for each of these nucleotides. So we have bromine 71. We're going to have our ratio here For our in value for neutrons. We're simply going to take the mask that we have, which is 71 subtracted by the protons in the atomic number, which is 35 and then divide that by our 35 as well or protons. And this is going to give us 1.03, which is less than 1.25. If it is less than 25, it is going to undergo positron emission as we said before or electron capture. So, so far we have one of the answers here and let's try for the other one. So we have burrow mean 86 And this ratio is going to be very similar. We're gonna do 86 -35, divided by 35. We're gonna get a ratio of 1.45, which is greater than 1.25. And if this is the case, it's going to undergo what's known as neutron emission or beta emission. So the question asks us which one is going to undergo positron emission and that is going to be our bromine 71 overall. I do hope this helped, and until next time.