Electron Capture & Positron Emission - Video Tutorials & Practice Problems

Electron Capture

Now, electron capture is what an unstable nucleus vouchers or absorbs an electron from the inner electron orbital. Now, here we're going to say this occurs in nuclei with an excess number of protons. So they would undergo electron capture to help us reduce the number of protons or as helping to increase the number of neutrons. Here, we're going to say that a proton and electron combined together to help us give us a neutron. So by creating this neutron, we actually bring down the number of protons, bringing them more in line with one another in terms of balance. Now, here we have SUSI 131 it's undergoing electron capture, meaning it's absorbing this electron. Remember that your mass number on both sides have to be the same and your total number of protons on both sides have to be the same. Here, we'd have 131 plus zero, gives me 131 55 minus one, gives me 54. If we look on the periodic table, the only element with an atomic number of 54 would be xenon. So here we'd say that si 131 undergoes electron capture and in the process, it produces xenon 131 as a product.

Positron Emission

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's symbolized as zero. 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 two 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 our proton splits into a neutron and a positron. And that's how we're going to limit the number of protons as we have an excess of them and help to increase the number of neutrons. Here we have CSI 130 C 130. It's going to do Positron emission. 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 the 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.

Electron Capture & Positron Emission Example

Here, we're told to write a nuclear reaction. For each. In the first one, we need to show electron capture of iridium 189. So iridium 189 William has an atomic number of 77. Now, meridian is one of my favorite elements. Uh So people theorize that the dinosaurs became extinct because a meteor crash landed into earth and extinguished all of them. Now, there's a scar in the Gulf of Mexico. And if you were to go there and collect samples from that spot, you would see that it's composed of iridium. Iridium comes from space from stars. So it's one of my favorite elements uh because of that little bit of trivia. So here we have meridian 189 it's undergoing electron capture. So that means it's going to absorb an electron. So our mass numbers need to be the same overall on the, on the product side. So 189 plus zero is 189 the number protons have to be the same on both sides. So this is 77 minus one, gives us 76. So here this would change into osmium. Another one of my favorite elements because it's one of the most dense elements that exists on earth. So now b we need to do positron emission of U um uranium 229. So we have 229 uranium which has an atomic number of 92 positron emission emission means it's a product. A positron is the anti electron. So it's a positive electron. And here we have uh 229 plus zero is 229. So mass numbers are the same on both sides. On the reactant side, we have 92 protons. On the product side, we need 92 protons. We have plus one, which would mean we need 91 more. And that would give me pa as my isotope. So these would represent our electron capture of uranium 189 and positron emission of uranium 229.

Provide a daughter nuclide when Rn-215 undergoes 2 sets of alpha decay and a positron emission.

• A.
• B.
• C.
• D.

Identify the missing species from the following nuclear reaction.

• A.
• B.
• C.
• D.