Radioactive Decay

Hey, guys, In this new video, we're gonna take a look at nuclear reactions. Now we're going to say here that nuclear reactions deal with chemical processes that take place in unstable nuclei atoms. Now, remember your basic picture of the atom we have spinning around the nucleus are electrons within our nucleus. We have our protons and neutrons are protons air positively charged are neutrons are neutral now, nuclear reactions deals with us somehow affecting the number of protons within our given. Adam, Now we're gonna say this normally happens with very large, bulky radioactive types of elements. Now, we're gonna stay here. Unlike normal chemical reactions where the identities of the elements stay the same, we're gonna say nuclear reactions often result in elements changing into completely different elements. So we're all used to stalk geometry and balanced chemical equations. For example, we're used to seeing we have H two gas here, plus n two gas here combined to give us NH three gas over here and balancing it. Here we put there's a two here we put it to here and a three here, but for nuclear reactions were actually affecting the number of protons within our element. Remember, your protons or your atomic number represents the identity of that element. Every element has its own unique atomic number that no other element has. But a nuclear reactions were actually messing around with the number of protons, which results in us creating completely new and different elements. So you could start out with calcium 20 and somehow go through some process in which calcium 20 I'm calcium 40. I mean becomes are gone. So that's the whole basis of nuclear reactions. We go from one element to a completely new element. By affecting the number of protons affecting number of protons has a direct impact on the identity of the element.

Now we're gonna say here, when it comes to nuclear reactions, we can think the British physicist Ernest Rutherford, who really did a lot of experiments with nuclear reactions His contribution to nuclear chemistry was so great that they actually named Element 104 after him. Element 104 is called Ruth or 40. Um So it's kind of Ahm bridge toe all the work that he's done in terms of this field. Now, Rutherford basically broke down nuclear reactions into three major types of categories. We have our Alfa decay and you may hear instead of alpha decay, you may hear Alfa emission. We also have beta decay, which you may also here as beta emission. And then finally, we have gamma emission. You tend to just hear it is gamma mission. You usually don't hear the term gamma decay. Now what is the word decay or mitt me? Well, that means that the radioactive particle will be a product. So remember, if you hear the word decay or emit for a mission, that means that the radioactive particle involved in all these reactions will be a product. Now the opposite of decay or meeting would be the word capture, so capture will be the complete opposite. Capture would mean that the radioactive particle involved and each of these types of nuclear reactions would be a reacted. So in Alfa decay, we emit an alpha particle. In beta decay, we emit a beta particle and gamma emission. We emit a gamma particle. These particles are what caused our elements to go from one type to another type. And what you have to remember is when they say DK or emission. They're saying that this alpha particle beta particle or gamma particle will be a product. But if you hear the term capture or even absorption, that means that the alpha particle, the beta particles gamma particle, will be reacted. And this has a profound difference on what exactly your products will be because you'll be emitting or decaying these particles along with a whole new element with it. So the farther into into this chapter we go, we'll learn that beyond these three, we also have positron emissions as well as electron capture. Those who come after we learn these first three major types. So just remember, in a regular chemical reaction, we start out with Let's say carbon, we end with carbon. But in the nuclear reaction were emitting or capturing radioactive particles. And as a result, that's gonna change the identity of my element. You could start that with calcium and end up with something completely different, like our God.

Hey, guys, In this new video, we're gonna take a look at Alfa Decay. So remember, Rutherford talked about the three major types off decays. There's Alfa decay, beta decay and gamma emission. Here we have Alfa Decay. We're gonna say alpha decay occurs when an unstable nucleus emits a particle composed of two protons and two neutrons. Now, just think about it. We say that our atomic mass equals the number of protons, plus the number of neutrons. So here are atomic masses. We lose two protons and two neutrons, so two plus two gives me four. Your atomic mass is protons and neutrons added, and your atomic number is just the number of protons, so the number of protons losses too. So we're gonna say the Alfa particle is represented by four for your atomic mass over to your atomic number. And here we have our Alfa symbol. Now, we can also say that on our periodic table we have an element that also has on atomic mass of four and an atomic number of two. That element is helium. So we can say that the alpha particle can also be represented by the element helium because helium has the same atomic mass as an Alfa particle and has the same atomic number as an Alfa particle. And remember, we're using the term decay. So the K means that this alpha particle will be, ah, product. So if we wanted to look at an example of this, we could think of, for example, on your periodic table, you could have polonium. When John, your periodic table is p o palladium, we're gonna say, Let's talk about isotope to 10 Now remember what these nuclear reactions that can happen with different isotopes of an element. So on your periodic table will be doing different types of the caves with different types of isotopes. So don't worry if your atomic mass on your periodic table doesn't match my atomic mass. That's because I'm dealing with a certain isotope of the element. Remember, isotopes have the same atomic number, so that the same element, but they have different number of neutrons, so we'll have different atomic masses. So here, polonium 2 10 means the atomic masses to 10. If you look on your periodic table, Polin IAM has an atomic number. Number of protons off 84. Now we're gonna undergo Alfa Decay. Alfa Decay means we're gonna spit out or emit a NALC a particle. You can represent it like this, or like this here, I'll just choose to show it as helium. So we're gonna emit for over two helium now, nuclear reactions air different from regular reactions. But there are some similarities. Just like you have to have a regular chemical reaction balanced. You have to have a nuclear reaction also balanced. So here are total atomic mass is to 10. Here we have already an atomic mass of four. So we need to create an element that when I added to the four, gives me back this mass of to 10. So the new element has to be 206 because 206 plus four gives me to 10. Also, your atomic numbers need to match on both sides. This atomic numbers, too. We need it to add up to 84. So we'd say that the new element would have toe have 82 because 82 plus two gives me 84. And what element would that be? Well, that would be led. So what we say here is that we'd say the alpha decay off. Puligny, Um 2. 10 creates a brand new element. Lead 206 Okay, the helium or the alpha particle is just something that we admit. That's just waste the new. The new element that we're concerned with is the lead 82 06 So this represents an Alfa decay, and it's a simple is that Make sure that your atomic masses add up on both sides. Make sure your atomic numbers add up on both sides.

Now, if we want to talk a little bit more about this alpha particle, we're gonna say in terms of size of radioactive particles were gonna say that the alpha particle is the largest, so it's bigger than your beta particle is bigger than your gamma particle, So your Alfa particle is the largest of them. Now it is the most damaging toe biological cells because it has the highest ionizing power. Which means that somehow if you got it into your body that it would just shred your insights, it would irradiate all of your biological cells in your body. Ah, person who is exposed to an alpha particle internally has very low chance of survival. The good thing is, because it has the highest ionizing power, and because it's so large, it's extremely difficult for to penetrate us, penetrate our skins and get into ourselves. So we're gonna say that has the lowest penetrating power we're gonna say that are close. Even the air around us provides protection against alpha particles getting into our bodies. Now, how could you get an Alfa particle inside of you? Maybe you work in a nuclear facility where you have contaminated water or contaminated food or there was some chemical leak and it got exposed in our environment in some way, and then you ingested it. But it's extremely hard for things like this to occur, so Alfa particles are extremely damaging to our insides. But the good thing is they're extremely hard to get into our bodies.

Now here we have to write the balanced nuclear equations for each other following Alfa emissions. So for Alfie mission again, that's the same thing as a decay. That means that the alpha particle will be a product. So here we have Curium 2 48. Remember these numbers here are atomic masses. You have to actually look on your periodic table to find out the atomic number of curium and bismuth. So cure him on our periodic table is 96. We know that we're going to basically emit an Alfa particle, so it's gonna have to be a product again. We have four already, so we have to make sure that the new element next to it adds up to 2. 48 on the other side. So it's gonna be 2 44 plus plus. Forgive me to 48 and down here, this house to be 94. And what does that give me that gives me P U plutonium and then bismuth 207 That's the atomic mass. The weight on the bottom would be 83. So we have B I, we admit a helium or alfa particle. So we have four here but we need to 07 So we had two or three over 81 and that gives me t all. It's that simple. Now, if they were to ask an Alfa Absorption or Alfa Capture and that means that these alfa particles wouldn't be would not be any more products. They'd be reacting. So, for example, you have 40/20 which is calcium, and then you do Alfa capture, so I'd be on the same side. And then all you have to do is just add these numbers up so it would be 40 plus four is 44 over 22 to give you a new element. So you just look on your periodic table and see what element has an atomic number of 22 that would represent an Alfa capture.

Hey, guys, In this new video, we're gonna take a look at beta decay. Now, we're gonna say that beta decay occurs when an unstable nucleus somehow emits a new electron. Now we're gonna say beta particle can be represented by E for the electron. I like trying here. We're gonna say much smaller than the other two subatomic particles. So the atomic mass can just be understood as zero. And here we're gonna say it. Atomic number is negative one because the atomic number is basically the number of protons. Since this is an electron, we're going to say that it's the opposite of a proton, which is one so an electron is negative one. Now, we're gonna say here beta decay can be represented when we emit a beta particle. So, for example, if we had Mercury and remember the 21 means that's its atomic math. So let's say we had mercury to one. If we look on our periodic table, Mercury has an atomic number off 80. We're gonna emit a beta particle. Now, remember, you're gonna say you're atomic masses have t equal each other on both sides of the arrow and your atomic numbers as well. Here. The electron has no mass. So the new element is gonna have a mass up to one. And then here we have to be very careful here. This is minus one. So minus one plus what gives me 80. Well, the answer would have to be 81 because 81 minus one gives me the 80 that I had originally. So just remember what? Remember that. So here would be t l. So this would be an example of a beta decay or a beta emission.

Now we're gonna say in terms of size, we know that the Alfa particles are the largest radioactive particle. So we're gonna say beta particles, therefore are smaller than alfa particles now, because they're smaller in size, they're gonna be less damaging if we ingest them. So here they're gonna have a lower ionizing power. But the problem here is because they're smaller, they're able to better penetrate into our skin. So here they're gonna have mawr penetrating power. And so to stop, you need a sheet of metal or large block of wood toe. Make sure beta particle does not enter inside of our bodies.

So here we have to write the balance Nuclear equations for each of the following beta emissions again. Beta decay. Beta emissions means that the beta particle will be a product. If they had said baited it capture or beta absorption, then it would be a reacted. So here we're starting out with magnesium 25. So that's the atomic mass. On our periodic table. Magnesium has an atomic number off 12. It's gonna emit a beta particle. So our new element that's being created would still have the same atomic mass. And then here, negative one. Plus what number gives me 12. It has to be 13 because 13 minus one gives me the 12 I started out with initially. So this element would be aluminum. Now, Ruffini, Um, are you one? 02 We're gonna see if we look in our periodic table roof in. IAM has an atomic number off 44. Again, we're gonna emit a beta particle, so this number stays 102 And this number here would have to be 45. So it goes upto Rh. Okay, so those were the examples off beta decays or beta emissions

now learning from what we covered with Alfa Decane, Beta k thus far, we have to try to answer this question. So here we have led to a weight is formed from thorium 2 32. How Maney, Alfa and Beta decays have occurred. So before even try to answer this question, let's just write down what exactly they're saying They're saying we created led to a weight so led to await It's gonna be a product. And the atomic number of lead, according to our periodic table, is 82 and they're saying it was formed from four E um 2. 32. Thorium has an atomic number off 90. Okay, so what we have to realize next is what exactly does an Alfa decay do? And what exactly does a beta decay do? So remember, in an Alfa decay, we emit Ah, helium particle or an alfa particle. But what does that do exactly to my element? If you go back and look, you should realize that an Alfa decay causes a decrease in your atomic mass, so it decreases atomic mass by four. And what else does it do? It also decreases your atomic number by two So those are the two changes that occur Because again, we're emitting Ah, helium particle or Alfa particle. So if you go from 40 calcium, you admit you admit a healing particle. What do you have now? You're gonna have this is gonna be 18. This is gonna be 36 you have are gone. So what happened? The calcium, its atomic mass, went from 40 to 36. So it lost four its atomic number one from 20 to 18 so it lost to next. Beta decay. What is beta decay due to my element, will you admit a beta particle, which is zero over negative one e So what that does is it increases your atomic number by one. It doesn't touch the atomic mass at all. And that's the key to this question. If we take a look back at our question now, we go from one atomic mass of to 32. One atomic mass of 208 That is a difference of what? 2 30 to minus 20 wait. That's a difference of 24. Beta decay has nothing to do with my atomic mass at all. It only affects my atomic number by increasing it by one. So if I decrease my atomic mass by four. How maney Alfa decays is that so? Remember, every out of the K, we lose four, right? So if we decreased by 24 each off of the case, four lost. So this represents six Alfa decays. Six Alfa decays must have occurred for us to lose an atomic mass of overall. So automatically, the answer is gonna be either a, B or C. Next, what else happens? We're gonna say, OK, if we're losing six off of the case, that means we're losing six. He Liam's right now. What we're gonna say here, we're gonna say six times four gives me 24 and six times to gives me 12. So let's come down here and write down what this is gonna be now. So we're gonna stay here and guys, we're gonna need some room to do this. So let me just take myself out of the image so we have more room to work with. Okay, so we we start out with thorium 2 32/90. We know we're gonna undergo six off of the case, which is a loss of 24 and I'll also 12 from the atomic number. What does this help to create? Well, this helps to create 208 here, and then we're gonna have 78 here. So if you look on your periodic table, look and see what element has 78 we're going to say that that is platinum. Okay, so six off of the case helps us create platinum initially. Now, what's the problem we need now Platinum to go to let remember what happens with beta decay. We're gonna stay with beta decay. Your atomic number changes by one. It increases by one, so you need to go from 78 82. So that's an increase of how much That's an increase of four for your atomic number. So that means you must have had four beta decays occur, So seize our answer. So we're gonna say four beta. The case means what it means that you admitted four of these guys here, which we can just simplify by saying that so you could just say four times zero is 04 times negative. One is negative for here. I'm just combining everything to make it easier for ourselves so you could write it like that. Or you could have just wrote written it. As for over e minus one. E. If you're professor wanted you to write out, the actual reaction would be best to short like this. But since here, I'm just asking you how maney baited a case occurred. You could just simply do it like this to make the math easier and faster to Dio, so see would be the answer. And if we wanted to show this in the best possible way, you come back and rewrite it as 2. 30 to 90 th and you say you have six Alfa decays, plus four baited. The case gives me 20 8/ to let. So if you're professor wants you to show the balanced equation, you have to show it like this. So hopefully you guys were able to realize that fundamentally, what happens with an Alfa decay, your atomic mass decreases by four year atomic number decreases by two. And what happens with the beta decay? Your atomic number increases by one knowing that Alfa decay affect your atomic mass. But beta decay doesn't was the key to answering this question correctly.

Hey guys in this new video, we're gonna take a look at gamma emissions. So here we're gonna say gamma radiation is related to the electromagnetic spectrum. Now, we're gonna say here, gamma rays have the highest energy and therefore they have the lowest or shortest wavelength and then they have the highest frequency. Mhm. So remember you have to remember from electromagnetic spectrum theory that when it comes to energy, energy and frequency are directly proportional. All that means is if one is high, the other one would be high. But when it comes to wavelength, wavelength is inversely proportional to the both of them. All that means is that wavelength is the opposite of the other two. If they're high it's low If it's high they're low. So it's the complete opposite of frequency and energy. And remember wavelength is just the distance From one wave to another wave. Where frequency is how many waves do you get within 1/2? So if your distance between waves, the crest, the tops of them is very large. That means you don't get many waves in a second. But if the wavelengths are very small, if the distance between them is very small, You can cram a bunch of them in within 1/2. Okay, so then you would say the frequency is extremely high and the energy is high. Gamma rays have the highest behind cosmic rays, cosmic rays would actually be a little bit higher than gamma rays. We usually don't hear about this in lecture. But in lecture, So strictly lecture, we're gonna say gamma rays have the highest energy and therefore they have the highest frequency and therefore the lowest or shortest wavelength. If you went beyond just general, kem you go into physics and other higher level sciences. They start talking about cosmic rays, which are then even higher than gamma rays. But for right now, just focused on the simple electromagnetic spectrum, gamma rays are going to have the highest energy.

now we're gonna say a gamma particle can be represented by 0/0. And the gamma symbol is this. Now you're gonna say because it's 0/0. You should realize that a gamma ray actually does not cause any change in your atomic mass or atomic number. And because of that we usually see it happening with alpha decay or beta decay. But what's the whole purpose of gamma mission then? Well we're gonna say when it comes to gamma mission it has to do with the absorption of energy. So here we're gonna say this wavy live line represents energy and this electron is in our first shell in our atom. So here in absorption the electron is gonna absorb that excess energy and become excited and use that extra energy just absorbed to jump up to either a higher shell number or to a higher orbital number. So basically if you go from one s to to us. So you're going from the first shell To the 2nd. Show that represents absorption. You could also go from the three s. 23 D. You can script skip three P. Altogether and just jump up straight to three D. Both of these examples represent absorption. The first one represents absorption when you jump from one shell to a higher shell and then the three S. The three D. Represents you absorbing energy and jumping up from a lower orbital to a higher orbital within the same shell. Both of them begin with the number three. So they're both within the third shell of your atom. But D orbital's have more energy than S orbital's. So if we saw this we'd have 40 over 20 calcium. It undergoes a gammy mission. And we'd say that that calcium has an electron that have just absorbed um energy and it's gonna become excited. So we put a little asterisks by it to show that it's in an excited state. So that would represent a gamma emission. Now we're gonna say that gamma particles they have the lowest ionizing power but they have the highest penetrating power. So if you're ever exposed to gamma mission like gamma radiation, it's basically a done deal, you're not gonna survive. Gamma radiation is extremely toxic to living tissue and biological systems. So any exposure to even the smallest amount of gamma radiation would completely eviscerate all the living cells and tissues within your body. So it has the lowest ionizing power, but it's still extremely dangerous.

Now if we go to this example, it says which of the following represents an element that has experienced a gamma emission. Here we have electron configurations for elements. Remember the normal pattern is you go from one S to to US 22 P. The three of us, the three P. For us etcetera. And remember gammy mission involves the excitation or the absorption of energy gets into an excited state. So you could actually have an electron skipping an entire orbital, Like it's supposed to be in the two s. But it gains so much energy, it skips to s. And goes to two p. Or you could have an electron gaining even more energy and going from two s. 23 s. So if we look the one that fits this excited state or this gamma emission state would have to be sodium because we're supposed to see one S followed by two S, followed by two P, Followed by three s. But what must have happened, this electron in here must have absorbed energy and therefore able to jump to a higher energy state. So the next one would be three p. So it skipped the three s. and went straight to three p. So this represents an element that has gained sufficient energy to become excited, which represents a gamma emission. So, remember Yemen mission may not change your atomic mass or atomic number like alpha decay or beta decay, but it still does affect the atom in some way

Hey, guys, In this new video, we're gonna take a look at electron capture. Now, the word capture we've been talking about this there is decay in a mission versus capture. Decane. A mission means that you're particle will be a product, but capture means that it'll be a reacted. And here we're talking about an electron. I remember an electron is really just a beta particle. So when we say electron capture, we're really saying beta capture. They're both dealing with an electron beta decay. The electron will be a product, but invade a capture or electron capture. It will be an reacted. So here we're gonna say electron capture involves the absorption, often electron, which remember, we saw as this symbol find unstable nucleus and is represented by the following reaction. So let's think of an example we could deal with Francie um, which is the metal most to the left and the lowest down group one A. So that's fr. And here we'll say we're dealing with isotope to 23. So here capture means that this electron is not gonna be a product, but it's gonna be a reacted. So we're gonna have Francie um 2 23. And Francine has an atomic number of 87. We're gonna absorb an electron. What effect is that gonna do? Well, it's gonna be 2. 23 plus zero. Gives me 2. 23 and then 87 minus one is gonna give me 86. So you become Radan. All right? Okay. So that represents the opposite of beta decay. Instead of doing beta decay, remission were doing beta capture, a k A. Electron capture.

now here. We have to say right balance nuclear equations for each of the following elements after undergoing electron capture. So remember Rutherford was the guy who came up with the three major types of nuclear reactions, and they named Element 104 after him. So here, Rutherford has an atomic number of 104 here. We're dealing with isotope to 63. We're gonna absorb an electron. So to 63 plus zero gives me to 63 104 minus one. Give me 103 And that will be L R for the next one. We're dealing with Nobel, Liam. Okay, so Nobel Prize, Nobel, Liam. So here, we're gonna have no belly, um, to 60 which is We absorbing electron. So to 60 plus zero is to 60 one or two minus one is one on one. That's M D. You'll find that a lot of elements around Nobel, you are named after states named after countries named after just inventors and physicists and scientists. So there's a lot of elements that are named after people we might have heard off or may not have heard off. So here we have 2 to 60/1. 01 m D. And finally we have led to 07 so this would be 207 The atomic number of lead is 82. We absorb an electron, so 207 plus zero is 207 80 to minus one is 81. So this would be an example of electron capture, which is the opposite of beta decay or a mission invaded a care admission. The electron is not a reactant but a product.

Hey, guys, In this new video, we're gonna take a look at positron emission. So here, we're gonna say positive positron emission occurs when an unstable nucleus emits a positron. Now, what's a positron? A positron is an anti particle of the electron. Remember, the electron is represented by this. Ah, positron is the opposite of that. So it looks like an electron. But instead of it having a negative sign, it'll have the opposite sign. So it'll be a positive electron. So a positron is considered just a positive electron. I know this is weird, but again, remember, we're dealing with nuclear reactions. So a lot of unaccustomed things that we are not used to seeing do occur. And one of them is this positron. So we're gonna say here, here's our positron now, because we're talking about the word emission again, Emission would mean decay, which means that this positron would be a product. So let's think of an example here. Einstein has its own element named after him Einstein E um, so Einstein E, um, we'll deal with isotope to 53 of Einstein E. Um, So Einstein, um, is yes. On our periodic table, it has an atomic number of 99 we're going to emit a positron. And because we're emitting a positron, let's see. So because the atomic masses zero the new elements still gonna be 53. But because the bottom is one what number plus one gives me 99 it have to be on 98. So here, that would just be CF. So this would be an example of a positron decay or positron emission.

now, based on that, let's answer these two questions. It says right balance nuclear equations for each of the following positron emissions. So again, you're positron will be a product. So here we're dealing with uranium to 35 uranium is you on your periodic table. It's gonna have an atomic number of 92. We emit a positron. So this is gonna be 2 35 and 91 plus one. It gives me 92 so 91 would be P a. Now, next one is radon, which is RN. Okay. Radan has an atomic number of 86. We admit a positron. So now the elements still gonna be 2. 22 and 85 plus one gives me the 86. So that's act idiom. Okay, so these would be two examples off our positron emission

now following what we've learned so far about all the different types of the case and emissions out there. Let's try our best to answer this one. So here we're gonna say a nuclei I'd off Valium or not, Valium story, Um 2. 25 undergoes three off of the case for beta decays and a gamma emission. What is the product? So remember, thorium has an atomic number of 90. It's gonna undergo three off of the case and off of the case basically produced the helium or Alfa particle plus four baited a case. So that's four electrons being admitted, plus gamma, which is 0/0. So basically, when you have three helium particles being admitted, that's three times four, which is 12 3 times to which is six four times zero, which is 04 times negative one, which is negative for again. This is not the proper way to write it. I'm just combining all the math just to make it easier for us to see what the answer is. So we're gonna say 12 here, so the new element would have to be to 13 because 12 plus 2 13 would give me the 25 I started out with and then here six plus this negative four gives me too. So it has to be 88 here because 88 plus two will give me back the 90 I started out with. So then we're gonna say we have 88. So that is our A, which is radium. And because we underwent a gamma emission, Technically, this would be in an excited state. So we put little Asterix there to show that it's an excited state. So that's all we have to do. And this top equation will be the correct way to write the equation, remember? Oops, Remember, I just combined everything. I just combined everything here to make the math easier. Easier for us to see what's going on. But it's this top equation. That's the correct format that your professor will be looking for. So just remember, fundamentally decay. The mission means the particle be a product. Capture or absorption means it will be a reacted. That's the key to this. And then just remembering what's an Alfa particle of beta particle? Positron, a gamma? All those different concepts