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Introduction to Resonance Forms .txt | The first one is, since lewis structures are electronic configurations, we only move electrons and we never move any atoms. Now, notice what this arrow represents. This arrow is known as arrow formulasm. A double headed arrow simply means two electrons are being moved. So in this case, I have two electrons moving from my pi bond, and they move on to one of the orbitals on the oxygen. And now I no longer have this because these electrons have moved here. |
Introduction to Resonance Forms .txt | A double headed arrow simply means two electrons are being moved. So in this case, I have two electrons moving from my pi bond, and they move on to one of the orbitals on the oxygen. And now I no longer have this because these electrons have moved here. So this is, once again, this arrow signifies movement of electrons and not movement of atoms. In other words, if I draw this molecule or this compound where I took this atom and placed the atom onto one of the orbitals here, so now there's a bond, a sigma bond between oxygen, carbon. This is not a resonant form. |
Introduction to Resonance Forms .txt | So this is, once again, this arrow signifies movement of electrons and not movement of atoms. In other words, if I draw this molecule or this compound where I took this atom and placed the atom onto one of the orbitals here, so now there's a bond, a sigma bond between oxygen, carbon. This is not a resonant form. This is not a lewis dot structure for formaldehyde. In fact, this is not even formaldehyde. It's another molecule. |
Introduction to Resonance Forms .txt | This is not a lewis dot structure for formaldehyde. In fact, this is not even formaldehyde. It's another molecule. It's another compound altogether. So, once again, in resonant forms, there's only movement of electrons, never movement of atoms. Notice another important point that we'll talk about in detail. |
Introduction to Resonance Forms .txt | It's another compound altogether. So, once again, in resonant forms, there's only movement of electrons, never movement of atoms. Notice another important point that we'll talk about in detail. In just a moment. There is a double headed arrow, like so, and this represents resonant forms, okay? And we'll see why this is different than equilibrium arrows. |
Introduction to Resonance Forms .txt | In just a moment. There is a double headed arrow, like so, and this represents resonant forms, okay? And we'll see why this is different than equilibrium arrows. In just a second, let's look at Nitromethane. We're going to do a second example in which we're going to draw the resonant forms. So Nitromethane has one N, two O's, one C and three H's. |
Introduction to Resonance Forms .txt | In just a second, let's look at Nitromethane. We're going to do a second example in which we're going to draw the resonant forms. So Nitromethane has one N, two O's, one C and three H's. So in order to draw our loose dot structures, let's count the balanced electrons. So we have three balanced electrons from H.
We have four balanced electrons from our carbon. So we have and that means we have five balanced electrons coming from N, and we have two OS. |
Introduction to Resonance Forms .txt | So in order to draw our loose dot structures, let's count the balanced electrons. So we have three balanced electrons from H.
We have four balanced electrons from our carbon. So we have and that means we have five balanced electrons coming from N, and we have two OS. That means we have twelve electrons, balanced electrons coming from oxygen. So altogether, we should have a total of 24 balance electrons, right? Twelve plus five plus four plus three should give us twelve. |
Introduction to Resonance Forms .txt | That means we have twelve electrons, balanced electrons coming from oxygen. So altogether, we should have a total of 24 balance electrons, right? Twelve plus five plus four plus three should give us twelve. So let's begin. We draw our carbon, our H atoms, three H atoms around carbon. Then we draw our end right next to our carbon. |
Introduction to Resonance Forms .txt | So let's begin. We draw our carbon, our H atoms, three H atoms around carbon. Then we draw our end right next to our carbon. And then two o's, like so. We start by creating sigma bonds or covalent bonds. One bond here, a bond here, a bond here between the HS, a fourth bond between the carbon and end. |
Introduction to Resonance Forms .txt | And then two o's, like so. We start by creating sigma bonds or covalent bonds. One bond here, a bond here, a bond here between the HS, a fourth bond between the carbon and end. So all the orbitals here are filled. Now we create a bond between sigma bond between o and this o here. Now we have 123-45-6789 711, twelve valve electrons left over. |
Introduction to Resonance Forms .txt | So all the orbitals here are filled. Now we create a bond between sigma bond between o and this o here. Now we have 123-45-6789 711, twelve valve electrons left over. So we create this pi bond here. We place two electrons onto our oxygen, like we did here, and three pairs of electrons here. So that means this guy has a negative charge, like this one has here. |
Introduction to Resonance Forms .txt | So we create this pi bond here. We place two electrons onto our oxygen, like we did here, and three pairs of electrons here. So that means this guy has a negative charge, like this one has here. This N has a positive charge because N likes to have five electrons. It only has four electrons here, and this has six. So it's neutral. |
Introduction to Resonance Forms .txt | This N has a positive charge because N likes to have five electrons. It only has four electrons here, and this has six. So it's neutral. So a plus charge and a minus charge creates a net charge of zero. And this does have a net charge of zero. Now, this isn't the only lewis dot structure. |
Introduction to Resonance Forms .txt | So a plus charge and a minus charge creates a net charge of zero. And this does have a net charge of zero. Now, this isn't the only lewis dot structure. If we move two electrons here and we take these two electrons and create a double bond here, we have the following a distant lewis structure. Basically, these guys flip. Now we have a negative charge here. |
Introduction to Resonance Forms .txt | If we move two electrons here and we take these two electrons and create a double bond here, we have the following a distant lewis structure. Basically, these guys flip. Now we have a negative charge here. We still have a positive charge here, and we have a neutral charge here. So once again, we have a combination of Lewis structures. And these guys are known as resonance forms. |
Introduction to Resonance Forms .txt | We still have a positive charge here, and we have a neutral charge here. So once again, we have a combination of Lewis structures. And these guys are known as resonance forms. And the entire concept is known as resonance. Now notice other structures exist. We could have simply taken this double bond, placed in here and created a plus two charge, a minus two charge, and a minus two charge. |
Introduction to Resonance Forms .txt | And the entire concept is known as resonance. Now notice other structures exist. We could have simply taken this double bond, placed in here and created a plus two charge, a minus two charge, and a minus two charge. So more Lewis structures do exist. And now we come to the most important point about resonant forms nitromethane. This compound does not spend half of its time as one resonant form and half of its time as the other. |
Introduction to Resonance Forms .txt | So more Lewis structures do exist. And now we come to the most important point about resonant forms nitromethane. This compound does not spend half of its time as one resonant form and half of its time as the other. It is a combination of the two. In other words, this arrow does not mean it's an equilibrium. In other words, our nitromethane doesn't spend half the time as this compound, and then it converts to this compound. |
Introduction to Resonance Forms .txt | It is a combination of the two. In other words, this arrow does not mean it's an equilibrium. In other words, our nitromethane doesn't spend half the time as this compound, and then it converts to this compound. The entire nitromethane is a combination of these two molecules. Its actual structure is somewhere in the middle of these two resonant forms. And let's look at the following important observation. |
Introduction to Resonance Forms .txt | The entire nitromethane is a combination of these two molecules. Its actual structure is somewhere in the middle of these two resonant forms. And let's look at the following important observation. So let's suppose we have some compound X and it occur and it reacts in some way, and it converts to a completely different molecule, different compound where the atoms have moved. And this is why. Now let's wait until equilibrium has been achieved. |
Introduction to Resonance Forms .txt | So let's suppose we have some compound X and it occur and it reacts in some way, and it converts to a completely different molecule, different compound where the atoms have moved. And this is why. Now let's wait until equilibrium has been achieved. So the arrows, the rates going forward and reverse are the same. Now notice that these two arrows are different than this arrow. Now let's suppose we have some compound A and B, which are resonance forms. |
Introduction to Resonance Forms .txt | So the arrows, the rates going forward and reverse are the same. Now notice that these two arrows are different than this arrow. Now let's suppose we have some compound A and B, which are resonance forms. Now, this once again, does not mean that A converts to B and then B converts to A. Right? What this means is that the actual form of this molecule is a combination of the two. |
Introduction to Resonance Forms .txt | Now, this once again, does not mean that A converts to B and then B converts to A. Right? What this means is that the actual form of this molecule is a combination of the two. It's somewhere in between. Our actual molecule that this resin forms represents is an A, nor is it D. It's somewhere in between. And let's call it C. Okay, so this is equivalent to some molecule C, which is a combination of these two molecules. |
Introduction to Resonance Forms .txt | It's somewhere in between. Our actual molecule that this resin forms represents is an A, nor is it D. It's somewhere in between. And let's call it C. Okay, so this is equivalent to some molecule C, which is a combination of these two molecules. And this arrow does not mean equilibrium. Our molecules here aren't at equilibrium. They're not converting from this form to that form at a dad form to this form. |
Molecular Orbital Formation Example .txt | So thus far we have combined a one S orbital and a one S orbital. And we've also combined a one S with a two P. In this lecture, we're going to combine a two p with a two P to four molecular orbitals. Now, the first thing we have to realize is that there are at least two different ways that we can orient our two p orbitals. In part A, we have a parallel orientation. In other words, our two p orbitals are simply parallel to one another. In Part B, we have an orthogonal or perpendicular orientation in which our one two p orbital is perpendicular to our second two p orbital. |
Molecular Orbital Formation Example .txt | In part A, we have a parallel orientation. In other words, our two p orbitals are simply parallel to one another. In Part B, we have an orthogonal or perpendicular orientation in which our one two p orbital is perpendicular to our second two p orbital. So let's see which one of these forms molecular orbitals. So let's begin with part B. In Part B, we have two ways that we can orient or combine them. |
Molecular Orbital Formation Example .txt | So let's see which one of these forms molecular orbitals. So let's begin with part B. In Part B, we have two ways that we can orient or combine them. We can either combine the positive of this with the positive of this, or we can combine the positive orbital here and the negative orbital here. Negative simply means we flip the signs. In other words, this green is the positive, this green is the negative. |
Molecular Orbital Formation Example .txt | We can either combine the positive of this with the positive of this, or we can combine the positive orbital here and the negative orbital here. Negative simply means we flip the signs. In other words, this green is the positive, this green is the negative. So let's begin by adding or by combining the positive two p and the positive to P. We get the following orientation. Now notice in this orientation we have the positive interacting in a bonding way with the positive and so that forms a bond. And here we have an anti bonding interaction because the negative of this two p orbital interacts with the positive section of this two p orbital. |
Molecular Orbital Formation Example .txt | So let's begin by adding or by combining the positive two p and the positive to P. We get the following orientation. Now notice in this orientation we have the positive interacting in a bonding way with the positive and so that forms a bond. And here we have an anti bonding interaction because the negative of this two p orbital interacts with the positive section of this two p orbital. So we have bonding and antibounding. So let's look at the negative. Or simply we're combining two p positive and two p negative. |
Molecular Orbital Formation Example .txt | So we have bonding and antibounding. So let's look at the negative. Or simply we're combining two p positive and two p negative. That means this becomes blue and this becomes green. So we have this orientation. Once again we have a negative interacting with a negative. |
Molecular Orbital Formation Example .txt | That means this becomes blue and this becomes green. So we have this orientation. Once again we have a negative interacting with a negative. So that means we get a bonding orientation and we have positive interacting with a negative to produce antibonding. So that means because we have bonding and antibonding, we have no net interaction. In other words, no net interaction because the bonding and the antibonding exactly cancel out. |
Molecular Orbital Formation Example .txt | So that means we get a bonding orientation and we have positive interacting with a negative to produce antibonding. So that means because we have bonding and antibonding, we have no net interaction. In other words, no net interaction because the bonding and the antibonding exactly cancel out. So this type of orthogonal orientation does not work. It does not create molecular orbitals. So let's go to the parallel. |
Molecular Orbital Formation Example .txt | So this type of orthogonal orientation does not work. It does not create molecular orbitals. So let's go to the parallel. So once again, in the parallel combination we have two different waves that we can combine. Remember, we're inputting two atomic orbitals, so we should get back two molecular orbitals. So let's go this way first. |
Molecular Orbital Formation Example .txt | So once again, in the parallel combination we have two different waves that we can combine. Remember, we're inputting two atomic orbitals, so we should get back two molecular orbitals. So let's go this way first. In other words, we're combining a two p positive and a two p positive. So we get this orientation. Notice we have positive interacting with a positive and negative interacting with a negative. |
Molecular Orbital Formation Example .txt | In other words, we're combining a two p positive and a two p positive. So we get this orientation. Notice we have positive interacting with a positive and negative interacting with a negative. So we have bonding interactions. Likewise, if we combine positive two p and a negative two p, we switch these guys. So this becomes a negative blue and this becomes a positive green and we have this orientation. |
Molecular Orbital Formation Example .txt | So we have bonding interactions. Likewise, if we combine positive two p and a negative two p, we switch these guys. So this becomes a negative blue and this becomes a positive green and we have this orientation. In this orientation we have positive and negative. So we have antiboming and antiboding. So there exists a notal plane smacked between these two guys. |
Molecular Orbital Formation Example .txt | In this orientation we have positive and negative. So we have antiboming and antiboding. So there exists a notal plane smacked between these two guys. Right in the middle. So that means there's no electron density here. So electrons can't be found on this node or nodal plane. |
Molecular Orbital Formation Example .txt | Right in the middle. So that means there's no electron density here. So electrons can't be found on this node or nodal plane. So this, in fact, creates this type of parallel orientation creates two molecular orbitals. One bonding and one anti bonding. So let's draw our energy diagram once again. |
Molecular Orbital Formation Example .txt | So this, in fact, creates this type of parallel orientation creates two molecular orbitals. One bonding and one anti bonding. So let's draw our energy diagram once again. Going up. Our energy increases. Going down. |
Molecular Orbital Formation Example .txt | Going up. Our energy increases. Going down. Our energy decreases. So since our two p orbitals are exactly identical, that means they're on the same energy level. So they're on the same level here. |
Molecular Orbital Formation Example .txt | Our energy decreases. So since our two p orbitals are exactly identical, that means they're on the same energy level. So they're on the same level here. Likewise, because they're identical. They each have one electron. Now these two electrons will want to go in this orbital. |
Molecular Orbital Formation Example .txt | Likewise, because they're identical. They each have one electron. Now these two electrons will want to go in this orbital. Or in that orbital. Well, probably this one. And that's because this one is more stabilizing. |
Molecular Orbital Formation Example .txt | Or in that orbital. Well, probably this one. And that's because this one is more stabilizing. It's stabilizing because it's lower in energy. And nature likes that. Nature creates a system in which the energy is lower than before. |
Molecular Orbital Formation Example .txt | It's stabilizing because it's lower in energy. And nature likes that. Nature creates a system in which the energy is lower than before. And so our electrons will combine to form our bonding molecular orbital. And notice that the spins are different. They're Opposites. |
Molecular Orbital Formation Example .txt | And so our electrons will combine to form our bonding molecular orbital. And notice that the spins are different. They're Opposites. And this fact is due the pole exclusion principle that states that any orbital has the maximum two electrons and these two electrons have opposite spins. Now notice that electrons can still go into this orbital, right? But they don't want to. |
Molecular Orbital Formation Example .txt | And this fact is due the pole exclusion principle that states that any orbital has the maximum two electrons and these two electrons have opposite spins. Now notice that electrons can still go into this orbital, right? But they don't want to. And so that's why you won't find electrons there. If the electrons do somehow end up in this orbital, this orbital will create a destabilizing effect. And that means the nuclei will repel one another and will try to break that covalent bond. |
Introduction to Entropy.txt | I will talk to you about the concept of entropy. So what is entropy? Well, the most basic definition of entropy is that entropy is the measure of a disorder. Every system the best and a very good definition because it's kind of vague and you can't quantify with that definition. You can't use numbers. So let's explore the concept of entropy using public probability, and maybe we can come up with a better definition using probability. |
Introduction to Entropy.txt | Every system the best and a very good definition because it's kind of vague and you can't quantify with that definition. You can't use numbers. So let's explore the concept of entropy using public probability, and maybe we can come up with a better definition using probability. Okay, so let's look at this system here. This system is composed of two containers connected by a bridge, and within the container, there are four different molecules. And these molecules are allowed to diffuse from one side to the other side. |
Introduction to Entropy.txt | Okay, so let's look at this system here. This system is composed of two containers connected by a bridge, and within the container, there are four different molecules. And these molecules are allowed to diffuse from one side to the other side. So let's see what's the most probable situation that we can get. Okay, so what's the likelihood that we're going to get four different molecules all on the left side? Well, this thing could only occur one time, or there's one way that this can occur. |
Introduction to Entropy.txt | So let's see what's the most probable situation that we can get. Okay, so what's the likelihood that we're going to get four different molecules all on the left side? Well, this thing could only occur one time, or there's one way that this can occur. So let's look at this side. What's the likelihood that you get two different molecules on the left side of the container or on the left container? Okay, well, there are six different ways that this can occur. |
Introduction to Entropy.txt | So let's look at this side. What's the likelihood that you get two different molecules on the left side of the container or on the left container? Okay, well, there are six different ways that this can occur. And this means this type of situation is six times as probable. That basically means that if you take a snapshot at any given time of this system, that this snapshot of this picture is more or six times more likely to occur. So now we can come up with a better definition of entropy using probability. |
Introduction to Entropy.txt | And this means this type of situation is six times as probable. That basically means that if you take a snapshot at any given time of this system, that this snapshot of this picture is more or six times more likely to occur. So now we can come up with a better definition of entropy using probability. Entropy is the tendency of a system to take its most probable form. So in the situation or in the system we have here, what's the most probable form? Well, it's clear that this one. |
Introduction to Entropy.txt | Entropy is the tendency of a system to take its most probable form. So in the situation or in the system we have here, what's the most probable form? Well, it's clear that this one. It must be this one. Okay, now you could imagine this is only with four molecules. You could imagine how unlikely this becomes when we get millions and billions of different molecules. |
Introduction to Entropy.txt | It must be this one. Okay, now you could imagine this is only with four molecules. You could imagine how unlikely this becomes when we get millions and billions of different molecules. Okay, this becomes much more likely with greater amount of molecules. Now let's explore the relationship between the second law of thermodynamics and entropy. In another video recently, the second law of thermodynamics basically states that heat cannot be completely converted into work. |
Introduction to Entropy.txt | Okay, this becomes much more likely with greater amount of molecules. Now let's explore the relationship between the second law of thermodynamics and entropy. In another video recently, the second law of thermodynamics basically states that heat cannot be completely converted into work. Here we will see a slightly different definition of the second law of thermodynamics. So let's explore these two isolated systems that are the same size, that have the same number of molecules and the same type of molecules. Which one do you think is more probable to occur? |
Introduction to Entropy.txt | Here we will see a slightly different definition of the second law of thermodynamics. So let's explore these two isolated systems that are the same size, that have the same number of molecules and the same type of molecules. Which one do you think is more probable to occur? Well, let's find out. Let's use entropy to find out. Okay, well, in this system, the molecules seem to be scattered as far away from each other as possible. |
Introduction to Entropy.txt | Well, let's find out. Let's use entropy to find out. Okay, well, in this system, the molecules seem to be scattered as far away from each other as possible. In this system, they're very structured. They're in one ball. Okay, so let's see which ones are more probable. |
Introduction to Entropy.txt | In this system, they're very structured. They're in one ball. Okay, so let's see which ones are more probable. So in this system, you have bunch of nuclei, positively charged nuclei close to each other. Now, positive charges repel. And so these guys are going to want to naturally move away from each other, as far away from each other as possible. |
Introduction to Entropy.txt | So in this system, you have bunch of nuclei, positively charged nuclei close to each other. Now, positive charges repel. And so these guys are going to want to naturally move away from each other, as far away from each other as possible. They, in fact, would want to form this structure here. Okay? So this more structured system will want to turn into this less structured system. |
Introduction to Entropy.txt | They, in fact, would want to form this structure here. Okay? So this more structured system will want to turn into this less structured system. Okay, so let's go back to our definition, or definitions of entropy. One definition states that entropy is the measure of this order of a system. So since this is more structured, there's more order, so it's less disordered. |
Introduction to Entropy.txt | Okay, so let's go back to our definition, or definitions of entropy. One definition states that entropy is the measure of this order of a system. So since this is more structured, there's more order, so it's less disordered. Okay? This means there is a lower entropy or low entropy because it's more structured, more ordered. Okay? |
Introduction to Entropy.txt | Okay? This means there is a lower entropy or low entropy because it's more structured, more ordered. Okay? Now, here it's the opposite. Since here there's less structure and less order, it's more disordered, so there is a higher entropy. Now let's go to our second definition of entropy, which basically states that entropy is the tendency of a system to take its most probable form. |
Introduction to Entropy.txt | Now, here it's the opposite. Since here there's less structure and less order, it's more disordered, so there is a higher entropy. Now let's go to our second definition of entropy, which basically states that entropy is the tendency of a system to take its most probable form. So, once again, which one is more probable? Well, this one is more probable. Therefore, there's a higher entropy, and this guy is less probable, so there's a lower entropy. |
Introduction to Entropy.txt | So, once again, which one is more probable? Well, this one is more probable. Therefore, there's a higher entropy, and this guy is less probable, so there's a lower entropy. Okay, so we can refine the second law of thermodynamics into the following. The second law of thermodynamics states that the entropy of an isolated system will never decrease. It will either stay the same, or it will increase. |
Hund’s Rule .txt | And they do so according to Coulomb's law, which is given by the following formula the force that at either charge field due to the other charges given by constant k times charge of one times charge of two divided by distance between them squared. So if I take two electrons, q one and q two a distance R apart this electron, this charge q two, will feel a force due to this charge q one, the same charge, and this force will be in this direction. And this force is given by this law. Likewise, this charge Q one will also feel a force due to this charge q two. And the force will be in the opposite direction with the same magnitude. And it's also given by this equation, Coulomb's law. |
Hund’s Rule .txt | Likewise, this charge Q one will also feel a force due to this charge q two. And the force will be in the opposite direction with the same magnitude. And it's also given by this equation, Coulomb's law. So what Coulomb's Law says is the following if we place two electrons next to each other, they will repel. They will create repulsion forces. So this leads into the following fact placing electrons into the same orbital in a subshell will create repulsion forces. |
Hund’s Rule .txt | So what Coulomb's Law says is the following if we place two electrons next to each other, they will repel. They will create repulsion forces. So this leads into the following fact placing electrons into the same orbital in a subshell will create repulsion forces. And this explains two ideas. This is why a maximum of two electrons can go into an orbital. Because if we place three, four or five electrons into the same orbital, this will increase our force dramatically, creating a lot of repulsion forces, creating a lot of repulsion. |
Hund’s Rule .txt | And this explains two ideas. This is why a maximum of two electrons can go into an orbital. Because if we place three, four or five electrons into the same orbital, this will increase our force dramatically, creating a lot of repulsion forces, creating a lot of repulsion. And that means this idea explains the Poly Exclusion Principle, which states that a maximum two electrons can be placed into any given orbital. Now, this principle also explains Honduras. And what Hungry states is the following. |
Hund’s Rule .txt | And that means this idea explains the Poly Exclusion Principle, which states that a maximum two electrons can be placed into any given orbital. Now, this principle also explains Honduras. And what Hungry states is the following. It says that electrons will not go into an occupied orbital occupied by some electron until all the orbitals within that subshell are already filled. So, for example, let's look at the electron configuration of nitrogen. And it's the following two electrons are placed into the one s orbital. |
Hund’s Rule .txt | It says that electrons will not go into an occupied orbital occupied by some electron until all the orbitals within that subshell are already filled. So, for example, let's look at the electron configuration of nitrogen. And it's the following two electrons are placed into the one s orbital. Two electrons are placed into the two s orbital, right? We're not placing three electrons into our s orbital or four electrons, because only a maximum of two electrons can go into any given orbital because of this principle that we mentioned above. Now, let's look at our p orbitals. |
Hund’s Rule .txt | Two electrons are placed into the two s orbital, right? We're not placing three electrons into our s orbital or four electrons, because only a maximum of two electrons can go into any given orbital because of this principle that we mentioned above. Now, let's look at our p orbitals. Remember, there are three p orbitals. And what Hungry tells us is that before we add two electrons into an orbital, first all the orbitals must be filled with at least one electron. And that's exactly why we first add one electron to the PX orbital. |
Hund’s Rule .txt | Remember, there are three p orbitals. And what Hungry tells us is that before we add two electrons into an orbital, first all the orbitals must be filled with at least one electron. And that's exactly why we first add one electron to the PX orbital. Then we add the second electron to the PY orbital. And then we're adding the third electron into the PV orbital to give us a total of two plus two, four plus three seven electrons. This nitrogen has seven protons and seven electrons in its neutral state. |
Hund’s Rule .txt | Then we add the second electron to the PY orbital. And then we're adding the third electron into the PV orbital to give us a total of two plus two, four plus three seven electrons. This nitrogen has seven protons and seven electrons in its neutral state. Now let's look at oxygen. Oxygen has eight protons, so it has eight electrons. So let's draw the electron configuration according to Hungry. |
Hund’s Rule .txt | Now let's look at oxygen. Oxygen has eight protons, so it has eight electrons. So let's draw the electron configuration according to Hungry. So two electrons are placed into s, and two electrons are placed into the two s. Right. So that's because of the poly exclusion principle. Once again it states a maximum. |
Hund’s Rule .txt | So two electrons are placed into s, and two electrons are placed into the two s. Right. So that's because of the poly exclusion principle. Once again it states a maximum. Two electrons will go into an orbital. Next, we begin filling our p orbitals. We have three p orbitals, and now we have four electrons. |
Hund’s Rule .txt | Two electrons will go into an orbital. Next, we begin filling our p orbitals. We have three p orbitals, and now we have four electrons. So first, we distribute the three electrons the following way. We place one into P, one into Y, and then one into D. And now, since all of them are filled, my fourth electron will go into filling completely this orbital. This PX orbital. |
Hund’s Rule .txt | So first, we distribute the three electrons the following way. We place one into P, one into Y, and then one into D. And now, since all of them are filled, my fourth electron will go into filling completely this orbital. This PX orbital. For example, if I dealt with the next atom, if I had one more electron, I place it into this y and if I had one more electron, I place it into my Z and I get a noble gas configuration. So Hans Rule can be represented in the following graphic way. So let's look at nitrogen. |
Hund’s Rule .txt | For example, if I dealt with the next atom, if I had one more electron, I place it into this y and if I had one more electron, I place it into my Z and I get a noble gas configuration. So Hans Rule can be represented in the following graphic way. So let's look at nitrogen. So here's my energy axis. And here's just my X axis. Now, this bar represents my one s orbital. |
Hund’s Rule .txt | So here's my energy axis. And here's just my X axis. Now, this bar represents my one s orbital. This black bar represents my two S orbital. The reason this one is lower than this one is because one s orbital is at a lower state energy state than the two s orbitals. And so the two s is a bit higher. |
Hund’s Rule .txt | This black bar represents my two S orbital. The reason this one is lower than this one is because one s orbital is at a lower state energy state than the two s orbitals. And so the two s is a bit higher. Likewise, the two PX and the two PX. Two PY and two PZ are higher than either this guy and this guy. That means they will be higher. |
Hund’s Rule .txt | Likewise, the two PX and the two PX. Two PY and two PZ are higher than either this guy and this guy. That means they will be higher. And these guys aren't the same level. So that means they will be at the same level. So now, when I place electrons, I place them in the following way. |
Hund’s Rule .txt | And these guys aren't the same level. So that means they will be at the same level. So now, when I place electrons, I place them in the following way. The upward arrow represents the electron spin of plus one half. The downward arrow represents the electron spin of negative one half. So first I draw my up arrow, my down arrow, and I finished with the one s.
Next, I put two electrons into my two s. Upward arrow, downward arrow. |
Hund’s Rule .txt | The upward arrow represents the electron spin of plus one half. The downward arrow represents the electron spin of negative one half. So first I draw my up arrow, my down arrow, and I finished with the one s.
Next, I put two electrons into my two s. Upward arrow, downward arrow. And finally, I put one electron in each. So I begin with the plus one. Half. |
Hund’s Rule .txt | And finally, I put one electron in each. So I begin with the plus one. Half. So upward, upward and upward. And now I'm done. This is my graphic representation of Hans rule for nitrogen. |
Hund’s Rule .txt | So upward, upward and upward. And now I'm done. This is my graphic representation of Hans rule for nitrogen. Now let's look at the graphic representation for Hans Rule for oxygen. So we start by drawing the same bars. And now we start filling our orbitals. |
Hund’s Rule .txt | Now let's look at the graphic representation for Hans Rule for oxygen. So we start by drawing the same bars. And now we start filling our orbitals. So up down. Up down, up up. And then I take my Fourth Electron and Final Electron and put it into my two X. |
Hund’s Rule .txt | So up down. Up down, up up. And then I take my Fourth Electron and Final Electron and put it into my two X. So I draw it down one. Because according to our rules, we can't have electrons that have the same spin in the same orbital. If we put two electrons in the same orbital, they must always have opposite spin. |
Acidity of Hydrides .txt | Now, any compound that's composed of two elements in which one element is a hydrogen is called a Hydride. Now, Hydrides have varying levels of acidity. They could be acidic, neutral, or basic. Now, if we look at our emeritus table, we see a trend. We see that as we go across the period from left to right, the acidity of Hydrides increases. And as we go down a group, the acidity of Hydride also increases. |
Acidity of Hydrides .txt | Now, if we look at our emeritus table, we see a trend. We see that as we go across the period from left to right, the acidity of Hydrides increases. And as we go down a group, the acidity of Hydride also increases. So that means atoms that exist on the left side of the period that form Hydrides are basic atoms that exist in the middle, that transition atoms or transition metals that form Hydrides with H form either mutual or basic Hydrides. And for the most part, atoms that I found on this part on the right side form either weak acids, strong acids, or neutral Hydrides. So for example, let's look at sodium and lithium and potassium. |
Acidity of Hydrides .txt | So that means atoms that exist on the left side of the period that form Hydrides are basic atoms that exist in the middle, that transition atoms or transition metals that form Hydrides with H form either mutual or basic Hydrides. And for the most part, atoms that I found on this part on the right side form either weak acids, strong acids, or neutral Hydrides. So for example, let's look at sodium and lithium and potassium. All these guys are found on the left side. That means they will form basic Hydrides. And in fact, all metal Hydrides are either basic or neutral Hydrides. |
Acidity of Hydrides .txt | All these guys are found on the left side. That means they will form basic Hydrides. And in fact, all metal Hydrides are either basic or neutral Hydrides. Now, we could also say, with the exception of one molecule, all nonmetal Hydrides are either neutral or acidic. The exception is ammonia. Ammonia is the only nonmetal that forms a weak base. |
Acidity of Hydrides .txt | Now, we could also say, with the exception of one molecule, all nonmetal Hydrides are either neutral or acidic. The exception is ammonia. Ammonia is the only nonmetal that forms a weak base. Now, let's examine the right side of the periodic table. On the right side, all the way on the right side, and all the way down, we see that we have strong acids. So HCL and HBR are both strong acids. |
Acidity of Hydrides .txt | Now, let's examine the right side of the periodic table. On the right side, all the way on the right side, and all the way down, we see that we have strong acids. So HCL and HBR are both strong acids. Now, because fluorine is found on the top, it's a weak acid. Remember, as we go up a group, the acid strength decreases. So this guy is a weak acid. |
Acidity of Hydrides .txt | Now, because fluorine is found on the top, it's a weak acid. Remember, as we go up a group, the acid strength decreases. So this guy is a weak acid. Water is neutral, so we leave that alone. Now, these two guys are weak acids as well, because remember, we move back a group, that means our acid strength decreased. So these guys are weak acids. |
Introduction to Molecular Orbitals .txt | Now, previously, we spoke about atomic orbitals and covalent bonds. In this lecture, we'll see how atomic orbitals of atoms combine to form covalent bonds, which are really molecular orbitals. So let's begin with the following simple example. So let's say we want to combine two neutral H atoms in a way to form a diatomic H two molecule. So we want to form a covalent bond. So what must happen first? |
Introduction to Molecular Orbitals .txt | So let's say we want to combine two neutral H atoms in a way to form a diatomic H two molecule. So we want to form a covalent bond. So what must happen first? Well, initially, these two mutual H atoms are very far apart. And since they're neutral, they each have a proton, a nucleus, and an electron surrounding that nucleus. So what happens as I begin to bring these molecules closer and closer and closer? |
Introduction to Molecular Orbitals .txt | Well, initially, these two mutual H atoms are very far apart. And since they're neutral, they each have a proton, a nucleus, and an electron surrounding that nucleus. So what happens as I begin to bring these molecules closer and closer and closer? Well, as I begin moving them closer, they begin to feel electrostatic force Coulomb's law. Now, as I move them closer and closer, eventually I will bring them to a point when the electrostatic repulsion of the nuclei of the protons down the nuclei will balance out the electrostatic attraction between the electrons and the protons in the nuclei. In other words, let's look at the following example. |
Introduction to Molecular Orbitals .txt | Well, as I begin moving them closer, they begin to feel electrostatic force Coulomb's law. Now, as I move them closer and closer, eventually I will bring them to a point when the electrostatic repulsion of the nuclei of the protons down the nuclei will balance out the electrostatic attraction between the electrons and the protons in the nuclei. In other words, let's look at the following example. So, when I have these two protons a certain distance apart, the repulsion between these two protons going this way will equal the attraction of these electrons. In other words, this proton of H atom one will attract the electron of H atom two. And likewise, H atom two will attract the electron of H atom one. |
Introduction to Molecular Orbitals .txt | So, when I have these two protons a certain distance apart, the repulsion between these two protons going this way will equal the attraction of these electrons. In other words, this proton of H atom one will attract the electron of H atom two. And likewise, H atom two will attract the electron of H atom one. And in fact, when there are 0.7
angstromes, angstrom simply means one times ten to the negative 10 meters apart. When they're this distance apart, a bond will form, a covalent bond will form. And in fact, as you move the two H atoms closer and closer from a far distance apart, energy begins to decrease until we reach this point, until we reach 0.7
angstromes away. |