Asalaamu alaykum everyone and today we are going to be talking about molecular orbitals. Now when we think of atoms we think of little ball thingies with sticks for the electrons that make the bonds. And you guessed it, it's highly inaccurate. And as we know a tongue these aren't just balls and sticks. Actually the nucleus doesn't look like a ball when you get to the more unstable atoms anyway. And we know about atomic orbitals and we know that they aren't electrons themselves. They are actually possible electron locations. And I've covered a lot about electron configuration and atomic orbitals in this video. We also know that an atom can take one of its atomic orbitals and hybridize them into hybrid atomic orbitals. Now I've talked about the changing structure of atomic orbitals in my SN2 video where I talked about the molecule changing from sp3 hybridized to sp2 hybridized. Well I didn't explain how this works. So here I am. Now hybrid atomic orbitals are the orbitals that make a covalent bond. Let's start with a molecule of hydrogen. Here is a diagram for hydrogen. Now to form the sigma bonds these will overlap and make one molecule which both electrons will reside in. Hydrogen molecule sit at a lower energy level than two lone hydrogen atoms because of the electrostatic interaction between each electron and the opposite nucleus. This is why hydrogen spontaneously forms diatomic orbitals. But the number of orbitals must be conserved. So when two atomic orbitals come together to form molecular orbitals they will form one bonding orbital and one anti-bonding orbital. Electrons in a covalent bond will sit in the lower energy bonding orbital as any orbital can hold up to two electrons. But if one electron were to become excited it will jump from the sigma or the bonding orbital to the sigma star or anti-bonding orbital. Now this is where hybridization comes into play. If an atom is participating in say a lot of bonds then it will utilize its hybrid atomic orbitals to form them. Let's say in CH4 carbon is making four bonds which is what CH4 is it takes its 2S orbital and all of its 2P orbital and hybridizes them to create 4SB3 hybridized hybrid atomic orbitals. Now what happens here is the 2S orbital will promote its electron to the 2P orbital and they will hybridize with like energy or degenerate forming SB3 hybridized orbitals. Now every energy level has 1S orbitals, 3P orbitals and 5D orbital. And I'm not going to talk about the F orbital. The number of bonds an atom can participate determines the number of atomic bonds that need to be hybridized to make hybrid atomic orbitals to generate bonds. Now let's look at an SB3 carbon which we just looked at. Typically participate in four sigma bonds just like methane. But carbon can also be SB2 or SB hybridized. Now the SB hybrid, SB2 hybridized orbitals have three electron domains which might happen if it has a bond to something. Let's look at C2H4. Now what happens here is just like methane, the carbon will promote one of its electrons but there will be one unhybridized orbitals. And that orbital will make the pi bond by overlapping with the other unhybridized orbital. Now this is the second bond of the molecule. And these overlap in perpendicular fashion by the way. Same goes for C2H2 which is a linear molecule with carbons having a triple bond with them. But there will be two unhybridized orbitals. And they will make two pi bonds and one sigma bond which gives three bonds which is why it's a triple bond. Sometimes we have to generate orbital diagrams for a molecule. Say a molecule of H2 there is one electron in this orbital and the other in the other orbital of the other atom and when they hybridize they form, they have two electrons in the bonding orbital. Now the bond order is the number of bonding electrons minus the number of anti bonding electrons divided by 2. So the bond order of hydrogen is 2 minus 0 divided by 2 which is 1. That's why hydrogen has only one bond. Let's look at a more complicated one like oxygen. Yes this diagram is scary and crazy. So the one S orbitals of both oxygen atoms are full so the bonding orbitals full and same for the 2S. So that orbital is also full and the 2P has Mrs. 4 bonds before getting full. So we can fill in the end counting out the bonding orbitals and the anti bonding orbitals electrons. We can find that the bonding order is 2. That's why oxygen has a double bond. Like this we can predict the bonding behavior of M2 given atoms. Let's look at an even scarier diagram of nitrogen. Now I'm not going to go over in detail as if you saw my hydrogen oxygen part then you don't know what's going on. Once we count we find that the bonding order is 10 minus 4 divided by 2 which is 3 so that's why nitrogen has a triple bond. So that's a lot about valence bond theory and atomic orbitals and with this hopefully you have a better understanding about atomic orbitals than the mathematical part that I haven't really explained too much in my previous video though you should check it out because that's going to be the first thing you will tackle. So that's all there is to it. Sorry if this was an extremely long video. This just atomic orbitals is a really complicated topic and we have more for later. So that's all there is to it. If you enjoyed and learned something from the video please like and subscribe for more videos about math and science and if anyone else is confused about this similar topic then please share the video to that person. And thank you for watching and I will see you next time. Bye!