Main menu

Pages

 

أضغط هنا وسجل رقمك وانتظر مكلمه


 

أضغط هناوشاهد اسمك


Hybridization of Atomic Orbitals - Sigma & Pi Bonds - Sp Sp2 Sp3



in this article we're going to talk about hybridization of atomic orbitals so what exactly is hybridization hybridization is basically combining atomic orbitals to make hybrid orbitals so for example the sp3 hybrid orbital is a blend of one s orbital and three p orbitals as you can see it's s1p3 sp2 squared is a hybrid of an s orbital and two p orbitals sp is a hybrid of s and 1p orbital so now you know what these terms mean so let's say if you were to see d2 sp3 this means that you're combining two d orbitals one s orbital and three p orbitals so what exactly is an s orbital an s orbital looks like a sphere and an orbital tells you the probability of finding an electron somewhere within an atom keep in mind electrons they can behave as particles and as waves so an orbital simply tells you the most probable location in which you could find an electron according to heisenberg's uncertainty principle we cannot know precisely the exact location of an electron now let's talk about the p orbital there's one s orbital but there's three different types of p orbitals you can have a p orbital in the x axis so this is known as p x you have a p orbital that's oriented along the y axis so that's called a py and then there's one oriented about the z axis which we'll call pz so there's three types of p orbitals now we're going to talk about the hybridization of carbon and the electron configuration of carbon is 1s2 2s2 2p2 so this is the electron configuration of carbon now let's focus on this portion let's say the 2s is at an energy level here and let's say this is 2p I want to highlight something so carbon has four valence electrons now when carbon forms an sp3 hybrid orbital it uses all four orbitals keep in mind sp3 means that we need to mix one s with three p orbitals so where should we put the sp3 orbitals should we put them at the same energy level with the 2s orbital or with the 2p orbital or somewhere in between and should it be like halfway closer to 2s or closer to 2p what would you say now to make an sp3 orbital it requires four orbitals as you can see here so one out of those four orbitals is s which means that the sp3 orbital has 25 percent s character now there's three p orbitals out of four orbitals three out of four correlates to 75 percent so the 75 p character so because the sp3 hybrid orbital is has more p character than s the energy level should be closer to 2p than it is a 2s so it should be somewhere over here now all four of these sp3 hybrid orbitals they're called degenerate orbitals degenerate orbitals are those that have the same energy so these four electrons will be placed in these four sp3 hybrid orbitals and you want to place the electrons one at a time when you're adding electrons to degenerate orbitals or orbitals of the same energy and that's uh the main idea behind hundred you want to add electrons with parallel spins one at a time if you're adding them to orbitals of the same energy now let's talk about the sp2 hybrid orbital let's talk about its energy first so to make an sp2 hybrid orbital we need one s orbital and two p orbitals so we have three p orbitals we're not going to use all three of them we only need to use two that means one of them will remain after hybridization so the green arrow would represent the process of hybridization so here's the unhybridized 2p orbital it has the same energy and now we have sp2 so one out of the three orbitals is s so this is we have 33 s character and two out of the three orbitals is p two out of three is about sixty seven percent if you round it so it's 67 percent p character so we still have more p character than s so therefore the sp2 hybrid orbital should still be closer to 2p than 2s it should be less than sp3 so these three orbitals will have the same energy since we use three orbitals to make them we're going to get three hybrid orbitals so i'm going to put one orbital in each i mean one electron in each orbital so we should have something that looks like this so these are the three sp2 hybrid orbitals now let's talk about the sp hybrid orbital so after hybridization to make the sp hybrid orbital we need one s orbital and one p orbital so we're going to use this s orbital and only one of the p orbitals which means the other two p orbitals are unhybridized so therefore they will be unaffected now if we have an s p orbital one is s one is p one out of two is fifty percent so therefore we have fifty percent s character and 50 p character so therefore the sp hybrid orbital should be right in between the s orbital and the p orbital and there's two of them since we use one s and one p orbital or two orbitals to make the sp hybrid orbital therefore there must be two hybrid orbitals so if you were to mix three atomic orbitals you should get three hybrid orbitals if you mix four atomic orbitals you should get four hybrid orbitals we're mixing one s one p that's a total of two atomic orbitals so that will give us two hybrid orbitals and they will h ave the same energy by the way you need to know that hybrid orbitals are used to form sigma bonds the unhybridized orbitals in this case the p orbitals that were unaffected and hybridized orbitals are used to make pi bonds which we'll talk more about later so just keep that in mind so pi bonds are always made from unhybridized p orbitals when you're dealing with carbon atoms and sigma bonds they form from the overlap of atomic orbitals and they consist of hybrid orbitals for the most part every single bond that you see contains one sigma bond every double bond has at least one sigma and it has one pi bond a triple bond contains one sigma and two bipods by the way a triple bond is stronger than a sigma bond or a single bond three bonds are more stronger than uh one bond it's harder to break three pencils than it is to break one so keep this in my triple bonds are stronger than single bonds but triple bonds are shorter than single bonds single bonds are longer but now if you compare one bond to another you need to know that well before I say it which one do you think is stronger a sigma bond or a pi bond what do you think about that sigma bonds are stronger than pi bonds the reason why a triple bond is stronger than a single bond is because you're comparing three bonds as opposed to one so these two sigma bonds let's assume they're equal the triple bond is going to win because it has two additional pi bonds so when comparing a triple bond versus the signal bond the triple bond is stronger because you compare three bonds compared to one but if we compare one sigma versus a pi bond the pi bond is weaker it's easier to break a pi bond but it's harder to break a sigma bond so just keep that in mind sigma bonds are stronger than pi bonds now let's say if you have a structure that looks like this how many sigma bonds are in this structure and how many pi bonds are there so every bond contains one sigma so one two three four five six seven therefore there are seven sigma bonds and every double bond has one pi bond so one two two pi bonds and that's a simple and easy way to count the number of sigma and pi bonds 

تعليقات


 

ابدا السحب من هنا



 

استلم الجائزة