Intro to Radioactivity - Video Tutorials & Practice Problems
Get help from an AI Tutor
Ask a question to get started.
1
concept
Intro to Radioactivity
Video duration:
2m
Play a video:
Hey everyone. So in our discussion of radioactivity, it's important to remember that radioactivity is just a process of spontaneous decomposition by an unstable nucleus. So remember decomposition means we're breaking down. We're going to say here that this instability that leads to decomposition is due to excess neutrons, more protons in the nucleus. And this in fact creates or produces a new element. And in the process, we emit some type of radiation. Now recall that when it comes to an isotope and subatomic particles, there are certain notations. You should remember when it comes to our isotope notation, which is this portion here. Remember X represents our element symbol. So for example, sodium and a mass number is represented by the variable a atomic number by C. Now, the number of neutrons that you have for your isotope is equal to a minus Z. Now, with this notation, it's also important to remember the notation for the different types of subatomic particles. When it comes to a proton, we could talk about its notation we'd say for proton, it is 1/1 P. When it comes to a neutron, it's going to be one over zero N notice here that our atomic number slot for P is one and for the neutron is zero. Meaning remember a proton is positive, a neutron is neutral. When it comes to an electron, it's going to be zero minus one E electrons are incredibly small, so small that their mass really doesn't amount to very much. So their mass number zero at the top electrons are negatively charged, which is why we have minus one here. And then e for electron, a positron is known as an anti electron or a positively charged electron. So here would still be zero since it's an electron doesn't weigh very much. It's an anti electron or positively charged electron. So this will be plus one. Then here we have e so this represents what radio radiation is. In terms of radioactivity. We're just breaking down our nucleus because of an excess of neutrons and protons. And here we have our different notations for our subatomic particles.
2
concept
Nuclear Reactions
Video duration:
1m
Play a video:
Up to this point, we've talked about chemical reactions in our earlier chapters. Now we're gonna take a look at nuclear reactions. We're going to say the differences between chemical and nuclear reactions are that chemical reactions, we have the number and type of elements on reacted and product side being conserved. So basically, you start out with five atoms of carbon on the reactant side, you should end with five atoms of carbon on the product side. This is different from nuclear reactions because with nuclear reactions, the identity of elements changes and that's happening because our number of protons are changing. However, with this change, we're gonna see that the overall mass number as well as the overall number of protons is conserved between reactants and products. So let's say you have five protons on the reactant side, your total number of protons on the product side should still stay five in this process. Though your beginning element will change identities. So as we delve deeper and deeper into our radioactive decays later on, we'll see how this applies.
3
example
Intro to Radioactivity Example
Video duration:
1m
Play a video:
So here in this example question, it says label each reaction as chemical or nuclear. Remember in chemical reactions, the identity of elements stay the same on both sides. But for a nuclear reaction, our elements change identity because we have a changing of the number of protons. If we take a look at the first one, we're starting out with oxygen 15. And if we look on the other side, oxygen is nowhere to be found. Instead, we have fluorine 15 and we actually have a positron here, the identity of our reaction has changed. So this would represent a nuclear reaction. For our second reaction, we have two magnesium atoms combining with one oxygen molecule to produce two magnesium oxide compound. Here, we're gonna say we have two magnesiums on both sides and two oxygens on both sides. The identity of our elements have not changed. So this is a chemical reaction or regular reaction. So this is how we'd identify both of these reactions given to us. In this example question.
4
concept
Understanding Nuclear Reactions
Video duration:
1m
Play a video:
Now, when it comes to a typical nuclear reaction, it consists of a parent nuclide, a Donner nuclide and an energetic particle. You're going to say that our nuclide is a radioactive isotope that has an unstable nucleus and emits radiation as it decays here, our parent nuclei is an unstable radioisotope and this is important. It appears on the reactant side. It's what you start with the daughter nuclide is the more stable radio isotope that appears on the product side. So remember a parent births a child births a daughter nuclide in this case. So we're going to say that we're starting out with the parent, the parent gives off a daughter nuclide which is more stable. If we take a look here in this example, we have our element X here. It's what we're starting with. This represents our parent, it emits or gives off these two products. This new isotope Y represents our daughter. And here we have remember this is an example of a positron, an anti electron. It represents our energetic particle. Now the energy particle itself, it can appear as either a reacting or a OK. So that one, it, it really just depends, you have to be on the lookout for the different types of subatomic particles we talked about earlier. Do they appear on the reactant side or the product side? But when it comes to the parent and the daughter, the parents is going to be the reactant and the daughter is going to be on the product side.
5
example
Intro to Radioactivity Example
Video duration:
45s
Play a video:
Here, it says to identify the energetic particle in the following nuclear reaction. In this nuclear reaction, we have thorium 231 it's going to decompose and it gives us a new isotope. So here this is protactinium 231 and it gives us this element here or this um notation here we have an E which stands for electron and negative one. So this electron represents our energetic particle. It is on the product side. But remember when it comes to en energetic particles, they can appear in either the reacting side or the product side. You just got to keep an eye out for them. OK. In this example, this represents our energetic particle.
6
concept
Types of Radioactivity
Video duration:
1m
Play a video:
Now there's a lot of types of radioactivity that exists. But when it comes to radioactivity in this course, we're going to say that there are five types of radioactivity. We have alpha decay, we have beta decay, we have um gamma emission and we have positronic mission when we say decay, when we say admission, they're synonymous with each other. OK. They mean the same thing when it comes to um decay or emission, this occurs when your energy particle is emitted from an unstable nucleus and is a product. So each one of these radioactive radioactive types have your energetic particle as a product. Now, with our next one, we call it electron capture electron capture. So we've section it off from the other four. That's because with electron capture the energetic particle is absorbed and because it's absorbed, it's going to be on a reacting side. So remember there's five major types of radioactivity. You need to remember four of them create an energetic particle as a product. And the final one electron capture has their energetic product at the very, very beginning of your nuclear reaction as a reactant
7
example
Intro to Radioactivity Example
Video duration:
1m
Play a video:
So in this example question, we have to identify the reactivity as either a decay or a capture. Now, for the first one, we have uh carbon 11, it decomposes to give us boron 11. And look our first energetic particle, this is a positron, it's listed as a product. So this would be a decay. Remember in a decay or emission radioactive process, your energetic particle will be a product in the next one. What do we have? We have an electron as a problem. So this is also a decay going to two. Here we have our energetic particle which is also an electron as a reactant when it comes to a capture type of radioactive process capture means that our energetic particle will be reacted, right. So this would be a capture. And the last one here again is another electron that is also a reactant. So this is also a capture. So remember with a decay or emission reaction, your energetic particle will be a product with a capture reaction. It has to be a reactant.
Do you want more practice?
We have more practice problems on Intro to Radioactivity