Alright. So here in this video, we're going to talk about some atomic properties and so each atom oven element has unique properties and we're going to talk about three specific properties that you all should be familiar with and we're going to talk about them in these three lines of text here. Now The very first property that you all should be familiar with is the atomic number. Now the atomic number is defined pretty simply. It's a pretty straightforward, easy idea. All it is is the total number of protons in the nucleus of an atom. And so all you need to do to get the atomic numbers count up the total number of protons and that's it. Now, the atomic number, or the total number of protons, is actually what defines each element. And so if we change the total number of protons in the nucleus of an atom, then we change the element that it falls under. However, if we change the other subatomic particles like neutrons or electrons, then we do not change the element and so on. Lee changing the number of protons or Onley changing the atomic number is going to change the element, and that's why the atomic number or the number of protons defines each element. So let's take a look at our example down below to clear some of this up. So here we're taking a look at the atomic properties of a carbon atom. More specifically, this carbon atom that we're showing you right over here. And so if we want to determine the atomic number, which is once again just the number of protons in the nucleus, all we need to do is count up the total number of protons in this nucleus over here. And so when we do that, what we'll see is that there are a total of six protons in the nucleus, which means that the atomic number of this Adam is six. And so, once again, the protons are here in red and we're just counting up the number of red circles here, and there are six of them, which is why the atomic number is six. So that's pretty straightforward. That's called the atomic number. Now, once again, if we were to add 1/7 proton in here, uh, then we would be changing the element and it would no longer be carbon. Instead, it would be nitrogen. And so the number of protons in the nucleus is going to define the element. Now, if we were to add another neutron here, pretend this were a gray circle. If we were to add another neutron, then it would still be a carbon. Adam, if we were to add another electron here in, uh, the, uh, revolving around the nucleus, Uh, then it would also still be a carbon atom. And so the number of electrons and neutrons do not affect the type of element that it iss. And once again, it's on Lee the number of protons that determines, uh, each element, and so that really that's it for the atomic number moving on. Now. What we have next is the mass number, and the mass number is also a pretty straightforward idea. It's really just the mass of the nucleus of a single Adam. And so if we want to take the mass of the nucleus, then we need to consider the subatomic particles that air inside of the nucleus, which we know are both protons and neutrons as well. And so the mass number is going to be the total number of protons and neutrons found in the nucleus. So once again, let's take a look at our example down below on DSO Of course, if we want to get the mass number, we need to get the mass of the nucleus and consider the number of protons and neutrons in the nucleus. We already know the number of protons. And so if we count the number of neutrons, the number of gray circles here in the nucleus, what you'll count is that there are a total of 612345 and six. So we can put a six here as well. And so if we want the mass number, all we need to do is total Up to two, we have six protons plus six. Uh, neutrons will give us the mass. Number six plus six is, of course, equal to 12. And so this is going to be the mass number that we just defined up above here now, last but not least, what we have here is the atomic mass, which is also sometimes referred to as the atomic weight. Now, the atomic mass or the atomic weight sounds kind of similar to this mass number idea, and really, they are very, very similar. However, there's one big difference, and this is the idea that the atomic mass or the atomic weight instead of being the mass of the nucleus of one Adam, it's actually going to be an average total mass of all of the atoms of an element. And so it is going to be an average. Whereas the mass number is not an average, it's the mass of just one Adam. Now, if we take a look at our image over here on the right hand side, which you'll notice is that a lot of periodic tables in your textbooks are gonna have a periodic table view that looks somewhat like this for the elements. And so when you see this view here, you'll notice that there are some specific labels here. Now, the very first one that you'll see here is this number up here, which is 12.11 now. This number here is what we refer to as the atomic mass or the atomic weight that we just talked about, which is once again an average total mass of all of the atoms of an element which is why it looks like a strange number here with the 0.11 Um and so once again, we'll be able to understand this idea here of atomic mass or atomic weight, much better later in our course, once we start talking about isotopes. But for now, what you should note is that the atomic mass is going to be very, very similar to the mass number of 12. Notice that they're very, very close. But they're going to be slightly different because once again, the atomic masses an average and we'll be able to understand that idea better in a different video once we talk about is Atos. Now notice that what we also have in here is the atomic number and the atomic number tells us the total number of protons in the nucleus, which we know is, ah, six here for the carbon atom. You'll also note that the chemical symbol is always going to be shown here for carbon. The chemical symbol, a C and the element name is usually provided as well, which is carbon. And so this year concludes our introduction to thes atomic properties of atomic number, mass number and atomic mass or atomic weight, and we'll be able to get some practice applying these concepts moving forward in our course, so I'll see you all in our next video.