Drawing Atomic Orbitals

now that we understand a little bit about how atomic orbital's can blend together into molecular Orbital's, I want to go back to the beginning and make sure that we all understand how to draw atomic orbital's correctly. So let's get started. So, thankfully, transforming a conjugated molecules into Atomic Orbital's Onley requires two steps, and they're super easy. So this lesson should be very easy for you. So rule number one, the number of atomic orbital's that you have in your molecule should be equal to the number of conjugated atoms that you have. So the rule basically states that you should have one atomic orbital drawn per conjugated Adam, so notice that in this molecule that I have drawn, it's an anti on. I actually four atoms one to Good, But let's look again. How many of those atoms actually have non bonding? Orbital's have orbital's that air not bonded to Adams? Well, it turns out that one doesn't count because it on Lee has orbital's that are attached to atoms, so that would not be a conjugated Adam. The other ones are conjugated, though, because we know that too has an orbital with an electron three has an orbital with an electron and then an anti in. Any time you see an an, I am. That means it's a lone pair with a negative charge. So those air non bonding orbital's. And for every non bonding orbital or conjugated Adam, you would have one atomic orbital. So that means that then I would just put three atomic orbital's. And this would just basically be for Adam to Adam three and Adam for easy enough, right? So then, Rule Number two says you need to know what type of pie electron contribution each type of non bonding orbital will have. So remember we went over the non bonding orbital's, and we said that there's different types, right? So let's just start from the beginning. Empty Orbital's and carbo cat ions donate zero electrons because they have zero electrons inside. Right pi bonds and radicals donate one each because in each situation there's one electron that's possible to be conjugated. Okay, and then, finally, a lone pair in an anti on notice that they have two electrons in the orbital's. They donate to each. Okay, so what you would do is you would count up the number of atomic orbital's that you have lined them up and then you would add in the number of pie electrons that are being contributed. Okay, so in the following examples, we're going to go over some molecules and we're gonna try to draw the atomic orbital's for them.

Let's do a first. So a, it says, provide the correct atomic orbital for the following conjugated molecules. So how? Let's start with number one. How many atomic orbital should there be on this molecule? Well, even though I see five atoms total total, the conjugated part is just this right, Because those are the only atoms that can resonate. So that means that I should have 1234 atomic orbital's. And I'm gonna draw them like this. Cool. Now I have to figure out how Maney pie electrons are being donated throughout the entire molecule. Okay, Now, one way to do this is to just count it up the way that I said, which is that every pi bon Adam donates one electron. Okay, so right now I have two pi bonds. But that therefore, Adams that inside those two pi bonds, right? So that means that each Adam would donate one electron, meaning that I would have 123 four. Okay, now, another shortcut that you can take that might be helpful is you can also just think that a pie bond total always don't need two electrons over two atoms. So another way you could think of it is that there's two electrons here. 234 electrons three and four are there, So there should be four total. Does that make sense? Because you have to hear. And then you have another two here, giving you a total of four. Okay, so I got to this answer using my definition. But you can also just use the shortcut that ah, pie bond always has two electrons that are being donated. Quote. So let's go ahead and try to try to do the second one on your own, and then I'll show you how.

So for the second one, provide the correct atomic orbital's. What I see is that the conjugated part of the molecule is this right. So how many atoms is that? It appears to be 12345 I have five. So let's draw that out. 12345 Cool. So that means that now I have tow count up my pie Electrons. Now my pie electrons We know that double bonds donate to each, so I'm gonna have to here. I'm gonna have to Here. I know that cat ions donate zero, right? So that means the total sum should be equal Toe four. I have four pi electrons total. Now I just have to put them in the right spots. And you would actually try toe line it up based on the order of these of these atoms. What I would do is I would do this one to nothing. 12 And what that shows me is that there are four pie. There are four pi conjugated electrons inside of five atomic orbital's. These. This would be the correct atomic orbital diagram for this molecule. Cool. Let's keep going

So what is the conjugated portion of this molecule? What I see is that it's actually quite long. It's all of this. 1234567 I'm gonna go ahead and write thes out. These air all conjugated to each other. So that means that my atomic orbital should have seven orbital's in it. Cool. And now we have to put in the correct amount of electrons. We know that each pi bon counters too. So that means I would have to here to here to here. And then what does the negative charge count? As if you look up on our little chart, It also counts Is too. So how maney pie electrons. We have total eight. So you have to put eight electrons into seven. And the way that we would draw this is to have one per orbital, except at the very end we're gonna put too, because that's where the anti honest. So we would draw like this 11111 and then finally 12 And that represents our and I am cool. So guys, these are our atomic orbital's. That says, the easy as it is, I'm glad we practiced this because this is going to be very important to understand how to draw molecular orbital. So let's go ahead and end this video and go to the next one.