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Definition of Temperature .txt | So one way to define temperature is to say that temperature is a property of matter that determines if energy transfer can occur. That is, if there is no difference in temperature. If the temperature of one object and a second object are the same, no energy transfer due to heat can occur. Okay? And that's pretty intuitive. Let's look at the second definition, the ideal gas law. |
Definition of Temperature .txt | Okay? And that's pretty intuitive. Let's look at the second definition, the ideal gas law. Well, the ideal gas law tells us that pressure times volume equals number of moles times a constant R times temperature t.
From that, when we keep pressure constant and the number of moles constant, we get Charles Law or v one over t one equals V two over t two. And when we graph this, we get the following. Suppose we graph it at one ATM, we get a linear relationship. |
Definition of Temperature .txt | Well, the ideal gas law tells us that pressure times volume equals number of moles times a constant R times temperature t.
From that, when we keep pressure constant and the number of moles constant, we get Charles Law or v one over t one equals V two over t two. And when we graph this, we get the following. Suppose we graph it at one ATM, we get a linear relationship. If we graph it at three ATM, we also get a linear relationship. If we graph it at five at M, we also get a linear relationship. Now, at any other temperature, it would also show a linear relationship. |
Definition of Temperature .txt | If we graph it at three ATM, we also get a linear relationship. If we graph it at five at M, we also get a linear relationship. Now, at any other temperature, it would also show a linear relationship. Now, one thing can be seen from this graph is that at every single temperature, the graph is a set at exactly one point. And that one point is right here on the x axis. And we can define temperature to be zero Kelvin at this point. |
Definition of Temperature .txt | Now, one thing can be seen from this graph is that at every single temperature, the graph is a set at exactly one point. And that one point is right here on the x axis. And we can define temperature to be zero Kelvin at this point. That is below this, right? It cannot exist. No temperature below this can't exist. |
Definition of Temperature .txt | That is below this, right? It cannot exist. No temperature below this can't exist. There are only temperatures above absolute zero. And that's another way to define temperature, using graphs and using equations. So this isn't that intuitive. |
Definition of Temperature .txt | There are only temperatures above absolute zero. And that's another way to define temperature, using graphs and using equations. So this isn't that intuitive. This is more intuitive. Now, the third definition is also intuitive. The third definition talks about thermal energy or a kinetic energy of a system. |
Definition of Temperature .txt | This is more intuitive. Now, the third definition is also intuitive. The third definition talks about thermal energy or a kinetic energy of a system. Now, remember, the kinetic energy is the translational energies plus the rotational energies plus the vibrational energies of a system, right? So when we talk about fluids, we talk about mainly translational and rotational energies. And we can formulate this formula here, which basically says translational energy plus rotational energy equals three over two times the constant K times temperature. |
Definition of Temperature .txt | Now, remember, the kinetic energy is the translational energies plus the rotational energies plus the vibrational energies of a system, right? So when we talk about fluids, we talk about mainly translational and rotational energies. And we can formulate this formula here, which basically says translational energy plus rotational energy equals three over two times the constant K times temperature. So from this equation, we see that if we increase temperature, we increase translational energy or the speed, and we increase rotational energy or the torque for solace. However, there's really no translational energies or rotational energies at low temperature. So we can't really have a relation between temperature and kinetic energy at low temperatures. |
Definition of Temperature .txt | So from this equation, we see that if we increase temperature, we increase translational energy or the speed, and we increase rotational energy or the torque for solace. However, there's really no translational energies or rotational energies at low temperature. So we can't really have a relation between temperature and kinetic energy at low temperatures. Now, at high temperatures, solids actually begin to translate and rotate slightly. So at high temperatures, we can't use this formula for solids. But what we could say is that for high temperatures, as temperature increases, so does the kinetic energy. |
Definition of Temperature .txt | Now, at high temperatures, solids actually begin to translate and rotate slightly. So at high temperatures, we can't use this formula for solids. But what we could say is that for high temperatures, as temperature increases, so does the kinetic energy. Now, one last thing I want to mention is from this definition, I said that temperature is a property. Now, more specifically, temperature is an intensive property. Now remember, when you divide an extensive property by another extensive property, you get an intensive property. |
Definition of Temperature .txt | Now, one last thing I want to mention is from this definition, I said that temperature is a property. Now, more specifically, temperature is an intensive property. Now remember, when you divide an extensive property by another extensive property, you get an intensive property. And I mentioned this in my previous video, okay? And we see this from this fact here. Kinetic energy, which is an extensive property. |
Definition of Temperature .txt | And I mentioned this in my previous video, okay? And we see this from this fact here. Kinetic energy, which is an extensive property. If you divide it by the number of moles, which is also an extensive property, you get temperature, right? And so extensive property divided by an extensive property gives you an intensive property. And so that's why temperature must be an intensive property. |
Solution formation and heat of solution .txt | Intermolecular bonds are non COBALTING forces that hold two or more different molecules in place. Suppose we have a single molecule. What holds that molecule in place? Well, covalent bonds or the shared electrons between different atoms of that same molecule hold that molecule in place. What holds a bunch of different molecules in place? Well, noncovalent forces such as dipole forces or lumpin forces hold these guys in place. |
Solution formation and heat of solution .txt | Well, covalent bonds or the shared electrons between different atoms of that same molecule hold that molecule in place. What holds a bunch of different molecules in place? Well, noncovalent forces such as dipole forces or lumpin forces hold these guys in place. And these forces are called intermolecular forces. So intermocular forces are simply non covalent bonds between different molecules. They hold different molecules in place. |
Solution formation and heat of solution .txt | And these forces are called intermolecular forces. So intermocular forces are simply non covalent bonds between different molecules. They hold different molecules in place. Now what are solutions? Solutions are mixtures of at least two compounds. Suppose we had a Beaker A with compound X and Baker B with compound Y? |
Solution formation and heat of solution .txt | Now what are solutions? Solutions are mixtures of at least two compounds. Suppose we had a Beaker A with compound X and Baker B with compound Y? Now suppose we wanted to make a solution out of compound X and Y. So we mix them. What would have to happen before a solution is formed? |
Solution formation and heat of solution .txt | Now suppose we wanted to make a solution out of compound X and Y. So we mix them. What would have to happen before a solution is formed? So by definition, we said solution formation is a formation of intermolecular bonds between X and Y. Well, before a bond is formed between X and Y, the bonds between the XS and the YS must break. So before X and Y forms a solution, intermolecular bonds between compound X and intermolecular bonds between compound Y must break. |
Solution formation and heat of solution .txt | So by definition, we said solution formation is a formation of intermolecular bonds between X and Y. Well, before a bond is formed between X and Y, the bonds between the XS and the YS must break. So before X and Y forms a solution, intermolecular bonds between compound X and intermolecular bonds between compound Y must break. Once all these intermocular bonds break, then intermolecular bonds between compounds X and Y must form. Now remember, the breaking of a bond is endothermic. So these guys are endothermic. |
Solution formation and heat of solution .txt | Once all these intermocular bonds break, then intermolecular bonds between compounds X and Y must form. Now remember, the breaking of a bond is endothermic. So these guys are endothermic. The formation of bonds is exothermic or energy is released. Now, from another lecture we saw that change in enthalpy is equal to a change in internal energy plus PD work done or the work done by the system on the environment to create that system. We also saw that if pressure is held constant and the number of moles is held constant, the change in volume is zero. |
Solution formation and heat of solution .txt | The formation of bonds is exothermic or energy is released. Now, from another lecture we saw that change in enthalpy is equal to a change in internal energy plus PD work done or the work done by the system on the environment to create that system. We also saw that if pressure is held constant and the number of moles is held constant, the change in volume is zero. If the change in volume is zero, this term becomes zero. So we can say change in enthalpy is simply equal to change in internal energy. Remember, when bonds are broken, reaction is endothermic. |
Solution formation and heat of solution .txt | If the change in volume is zero, this term becomes zero. So we can say change in enthalpy is simply equal to change in internal energy. Remember, when bonds are broken, reaction is endothermic. Okay? Energy is required to break a bond. So the enthalpy of this system, of this guy is positive. |
Solution formation and heat of solution .txt | Okay? Energy is required to break a bond. So the enthalpy of this system, of this guy is positive. Enthalpy change of this guy is also positive. Now, when bonds are formed, energy is released, they're exothermic. So the formation of Ynex is negative. |
Solution formation and heat of solution .txt | Enthalpy change of this guy is also positive. Now, when bonds are formed, energy is released, they're exothermic. So the formation of Ynex is negative. Now if we add all these guys up, we get something called heat of solution. And heat of solution can tell you if the solution formation is exothermic or endothermic. Now if this guy is negative, it's exothermic. |
Solution formation and heat of solution .txt | Now if we add all these guys up, we get something called heat of solution. And heat of solution can tell you if the solution formation is exothermic or endothermic. Now if this guy is negative, it's exothermic. And bonds formed are stronger or more stable than the bonds broken. So this bond between X and Y is greater or is stronger and more stable than that bond or this bond. If the heat of solution is positive, the bonds formed are weaker than the bonds broken. |
Solution formation and heat of solution .txt | And bonds formed are stronger or more stable than the bonds broken. So this bond between X and Y is greater or is stronger and more stable than that bond or this bond. If the heat of solution is positive, the bonds formed are weaker than the bonds broken. So the bond here is weaker and less stable than the bond here. Or here. Now, entropy will never tell you if a solution is spontaneous. |
Solution formation and heat of solution .txt | So the bond here is weaker and less stable than the bond here. Or here. Now, entropy will never tell you if a solution is spontaneous. Likewise, heat of solution does not tell you if a reaction is spontaneous. Now, remember, only entropy dictates spontaneity. Luckily, solutions usually increase in entropy, and entropy determine spontaneity. |
Solution formation and heat of solution .txt | Likewise, heat of solution does not tell you if a reaction is spontaneous. Now, remember, only entropy dictates spontaneity. Luckily, solutions usually increase in entropy, and entropy determine spontaneity. Now, under right conditions, solutions are usually spontaneous. And that's because entropy is increased. It's not because the reaction is exothermic. |
Effective Nuclear Charge and the Shielding Effect .txt | The force on either of the proton or the electron is given by k, a constant times q one, the q, or the charge of the protons times q two, the charge, the electrons divided by the distance between them squared. And what Coulomb's law does, it describes the force and electron experiences due to the pull of the proton nucleus. So let's look at two atoms, and let's compare these guys. First, let's look at hydrogen, and then let's look at helium. Well, recall that hydrogen has exactly one proton and one neutron in its neutral state. And that means we can find the electrostatic force or the pull on this electron due to this proton by simply applying our coulombs equation. |
Effective Nuclear Charge and the Shielding Effect .txt | First, let's look at hydrogen, and then let's look at helium. Well, recall that hydrogen has exactly one proton and one neutron in its neutral state. And that means we can find the electrostatic force or the pull on this electron due to this proton by simply applying our coulombs equation. And this guy states that our force due to this electron or on this electron due to this proton is given by k, a constant times the charge of our proton, times the charge of our electron divided by our distance r between them squared. And this is the force that this guy feels due to this guy and also the force that this proton feels due to this electron. Now, note that their forces are negative, but they have the same magnitude. |
Effective Nuclear Charge and the Shielding Effect .txt | And this guy states that our force due to this electron or on this electron due to this proton is given by k, a constant times the charge of our proton, times the charge of our electron divided by our distance r between them squared. And this is the force that this guy feels due to this guy and also the force that this proton feels due to this electron. Now, note that their forces are negative, but they have the same magnitude. So now let's look at helium. Remember, the outermost electrons are the electrons that will be pulled away. The inner electrons found on lower energy levels will not be pulled away first. |
Effective Nuclear Charge and the Shielding Effect .txt | So now let's look at helium. Remember, the outermost electrons are the electrons that will be pulled away. The inner electrons found on lower energy levels will not be pulled away first. So in helium, we now have two protons and two electrons. So our nucleus is composed of two protons, and our shells are composed of one electron each. So now we have an inner shell and an outermost shell. |
Effective Nuclear Charge and the Shielding Effect .txt | So in helium, we now have two protons and two electrons. So our nucleus is composed of two protons, and our shells are composed of one electron each. So now we have an inner shell and an outermost shell. And recall that electrons on the outermost shell will be pulled away. So this is the electron we have to worry about. This is the electron that will be pulled away. |
Effective Nuclear Charge and the Shielding Effect .txt | And recall that electrons on the outermost shell will be pulled away. So this is the electron we have to worry about. This is the electron that will be pulled away. So if we calculate the force that this guy experiences due to this proton nucleus, we'll see a discrepancy. And this discrepancy comes from something called the shielding effect. Now, this innermost atom or this innermost electron creates a shielding effect. |
Effective Nuclear Charge and the Shielding Effect .txt | So if we calculate the force that this guy experiences due to this proton nucleus, we'll see a discrepancy. And this discrepancy comes from something called the shielding effect. Now, this innermost atom or this innermost electron creates a shielding effect. In other words, inner electrons surrounding our nucleus shield the outermost electron from some of that charge due to our protons decreasing the net pull of the nucleus on our outermost electron. Now, the final amount of charge felt by this outermost electron due to our proton nucleus is called the effective nuclear charge. In other words, because there is a second electron found even closer to our nucleus, that means the charge that this guy will feel due to this proton nucleus will be less than what it would feel if this electron wasn't here. |
Effective Nuclear Charge and the Shielding Effect .txt | In other words, inner electrons surrounding our nucleus shield the outermost electron from some of that charge due to our protons decreasing the net pull of the nucleus on our outermost electron. Now, the final amount of charge felt by this outermost electron due to our proton nucleus is called the effective nuclear charge. In other words, because there is a second electron found even closer to our nucleus, that means the charge that this guy will feel due to this proton nucleus will be less than what it would feel if this electron wasn't here. That means if we use the same exact formula for Coulomb's law for this guy, we'll get this result. In other words, the force that this guy feels this charge due to our proton nucleus. This guy divided by R squared times K will be greater than the actual force that this guy feels. |
Effective Nuclear Charge and the Shielding Effect .txt | That means if we use the same exact formula for Coulomb's law for this guy, we'll get this result. In other words, the force that this guy feels this charge due to our proton nucleus. This guy divided by R squared times K will be greater than the actual force that this guy feels. Why? Well, because some of its positive charge will be dissipated to this electron. So that means our final effective nuclear charge will be less. |
Effective Nuclear Charge and the Shielding Effect .txt | Why? Well, because some of its positive charge will be dissipated to this electron. So that means our final effective nuclear charge will be less. So the way we find our effective nuclear charge is using the following formula. Our effective nuclear charge given by ZF equals to the nuclear charge or the actual nuclear charge of our proton nucleus minus the average number of electrons separating our outermost electron and our proton nucleus. And we see that for helium, if our nuclear charge on our proton nucleus is two, then this guy actually feels a charge of 1.69, because we're subtracting the charge that this guy experiences. |
Effective Nuclear Charge and the Shielding Effect .txt | So the way we find our effective nuclear charge is using the following formula. Our effective nuclear charge given by ZF equals to the nuclear charge or the actual nuclear charge of our proton nucleus minus the average number of electrons separating our outermost electron and our proton nucleus. And we see that for helium, if our nuclear charge on our proton nucleus is two, then this guy actually feels a charge of 1.69, because we're subtracting the charge that this guy experiences. So at the end, this atomos electron will experiences on average less pole. So let's compare the effective nuclear charge of the following two atoms. Let's look at lithium and Beryllium. |
Effective Nuclear Charge and the Shielding Effect .txt | So at the end, this atomos electron will experiences on average less pole. So let's compare the effective nuclear charge of the following two atoms. Let's look at lithium and Beryllium. Now, notice that Beryllium is one guy over to the right on their periodic table. That means it has four protons and four electrons, while lithium has three protons and three electrons. Let's compare the atomic structure. |
Effective Nuclear Charge and the Shielding Effect .txt | Now, notice that Beryllium is one guy over to the right on their periodic table. That means it has four protons and four electrons, while lithium has three protons and three electrons. Let's compare the atomic structure. So, the atomic structure of lithium is the following. Two of its electrons are found in the innermost shell, the one s shell. And one electron, because it only has three electrons, is found in the outermost two s shell. |
Effective Nuclear Charge and the Shielding Effect .txt | So, the atomic structure of lithium is the following. Two of its electrons are found in the innermost shell, the one s shell. And one electron, because it only has three electrons, is found in the outermost two s shell. Now, let's look at the comic structure of Beryllium. This guy has one extra electron or one more electron than lithium. Now, that means that it also just like lithium has two electrons on the one s in it orbital. |
Effective Nuclear Charge and the Shielding Effect .txt | Now, let's look at the comic structure of Beryllium. This guy has one extra electron or one more electron than lithium. Now, that means that it also just like lithium has two electrons on the one s in it orbital. But now, because it has an extra electron, it has two electrons in the outermost two s orbital. So the ratio in lithium of inner electrons to outer electrons is two to one, while the ratio of inner to outer electrons in Beryllium is two to two. So the ratio is greater in this guy. |
Effective Nuclear Charge and the Shielding Effect .txt | But now, because it has an extra electron, it has two electrons in the outermost two s orbital. So the ratio in lithium of inner electrons to outer electrons is two to one, while the ratio of inner to outer electrons in Beryllium is two to two. So the ratio is greater in this guy. The significance of this is the following. Because our ratio of inner to outer is greater, that means the inner electrons will take away or shield more charge. So lithium will experience a strong shielding effect due to these inner electrons. |
Effective Nuclear Charge and the Shielding Effect .txt | The significance of this is the following. Because our ratio of inner to outer is greater, that means the inner electrons will take away or shield more charge. So lithium will experience a strong shielding effect due to these inner electrons. So this single hour electron will not experience as much charge as it would if these guys weren't here. Now, let's compare this guy. Notice that in this guy we have one more electron in our outer shell. |
Effective Nuclear Charge and the Shielding Effect .txt | So this single hour electron will not experience as much charge as it would if these guys weren't here. Now, let's compare this guy. Notice that in this guy we have one more electron in our outer shell. And what that basically means is that because our ratio of eight to outer is smaller, that means this shielding effect will not be as great, because now we have an extra electron floating around our shell. So these guys will experience more charge than Dixon electron on the lithium. And what that means is that these two electrons will be pulled closer to the nucleus than here. |
Effective Nuclear Charge and the Shielding Effect .txt | And what that basically means is that because our ratio of eight to outer is smaller, that means this shielding effect will not be as great, because now we have an extra electron floating around our shell. So these guys will experience more charge than Dixon electron on the lithium. And what that means is that these two electrons will be pulled closer to the nucleus than here. And therefore the radius of this atom will be smaller than the radius of this atom. And that's because of the following. They both have a one s and a two s orbital. |
Effective Nuclear Charge and the Shielding Effect .txt | And therefore the radius of this atom will be smaller than the radius of this atom. And that's because of the following. They both have a one s and a two s orbital. So technically, their radius should be the same. But it's not. It's smaller in this guy because it has a weaker shielding effect. |
Effective Nuclear Charge and the Shielding Effect .txt | So technically, their radius should be the same. But it's not. It's smaller in this guy because it has a weaker shielding effect. In other words, the two electrons found on the outermost atom on the outermost shell experience more charge and so therefore are pulled closer. So, once again, the shielding effect is not as great in Beryllium as it is in lithium because the extra electron in Beryllium is added to the same energy level. The same two S orbital. |
Aufbau Principle and Electron Configuration .txt | In this lecture, I'd like to talk about the concept of electron configuration. But before we get into that, it's really important to talk about the following principle known as the AFP principle. Now, this principle will help us explain electron configuration. Now, what this principle states is the following. Whenever an atom adds a new proton to create a new atom element, it must also add another electron to neutralize that extra charge that comes from that extra proton. So the problem is the following whenever we add a proton, we know exactly where our proton goes. |
Aufbau Principle and Electron Configuration .txt | Now, what this principle states is the following. Whenever an atom adds a new proton to create a new atom element, it must also add another electron to neutralize that extra charge that comes from that extra proton. So the problem is the following whenever we add a proton, we know exactly where our proton goes. That proton goes into the nucleus along with all the other protons. What about our electrons? We have options as to where to place those electrons. |
Aufbau Principle and Electron Configuration .txt | That proton goes into the nucleus along with all the other protons. What about our electrons? We have options as to where to place those electrons. Because we have many different shells, we have many different subshells and we have made different orbitals within our subshells. So. Luckily, nature always tends to form the lowest possible energy state. |
Aufbau Principle and Electron Configuration .txt | Because we have many different shells, we have many different subshells and we have made different orbitals within our subshells. So. Luckily, nature always tends to form the lowest possible energy state. Therefore, whenever we add electrons to our atom, that electron will go into the lowest possible subshell. Lowest possible energy subshell. So let's examine the following concepts, and I state the following as electrons move further from the nucleus, our energy level will increase. |
Aufbau Principle and Electron Configuration .txt | Therefore, whenever we add electrons to our atom, that electron will go into the lowest possible subshell. Lowest possible energy subshell. So let's examine the following concepts, and I state the following as electrons move further from the nucleus, our energy level will increase. And this is true. Now let's examine why it's true. Well, let's look at the following illustration. |
Aufbau Principle and Electron Configuration .txt | And this is true. Now let's examine why it's true. Well, let's look at the following illustration. Suppose we have a proton now, a nucleus. And this is an electron. A distance. |
Aufbau Principle and Electron Configuration .txt | Suppose we have a proton now, a nucleus. And this is an electron. A distance. R away from it. Now Coulomb's law will give us some force that this guy feels due to this electron. And then it will also give us the same force, except in negative direction, that this guy feels due to this proton. |
Aufbau Principle and Electron Configuration .txt | R away from it. Now Coulomb's law will give us some force that this guy feels due to this electron. And then it will also give us the same force, except in negative direction, that this guy feels due to this proton. Now, my question is, how do we get this electron not a distance our way, but a distance to our way? In other words, how do we move this electron from this guy from this distance to this distance? Well, remember, if this is a positive force and this is a negative force, these guys are tracting. |
Aufbau Principle and Electron Configuration .txt | Now, my question is, how do we get this electron not a distance our way, but a distance to our way? In other words, how do we move this electron from this guy from this distance to this distance? Well, remember, if this is a positive force and this is a negative force, these guys are tracting. They want to come close. So in order for me to move this guy a distance R here a distance two R from our nucleus. That means I have to do work on that electron. |
Aufbau Principle and Electron Configuration .txt | They want to come close. So in order for me to move this guy a distance R here a distance two R from our nucleus. That means I have to do work on that electron. So if We Consider Our Proton And our electron a system, that means I have to do work on my system to move this electron a distance r away from this electron, right? So that means work must be done on our system. And because work is a transfer of energy, energy must be transferred into our system. |
Aufbau Principle and Electron Configuration .txt | So if We Consider Our Proton And our electron a system, that means I have to do work on my system to move this electron a distance r away from this electron, right? So that means work must be done on our system. And because work is a transfer of energy, energy must be transferred into our system. So our overall energy of our system increases as the electron moves away from our nucleus. And that's exactly why placing electrons further away from our nucleus will increase the energy of our system. That's exactly why nature tends to place electrons as close to our atom, as close to our nucleus as possible. |
Aufbau Principle and Electron Configuration .txt | So our overall energy of our system increases as the electron moves away from our nucleus. And that's exactly why placing electrons further away from our nucleus will increase the energy of our system. That's exactly why nature tends to place electrons as close to our atom, as close to our nucleus as possible. Because placing it further away increases the energy of our system. And nature tends to take the lowest energy state. So that's exactly why when we look at the principal quantum numbers as our principal quantum numbers increase as we go from n equals one to n equals two to n equals three, or from Orbital S P to D. Our energy will increase as we go down this table. |
Aufbau Principle and Electron Configuration .txt | Because placing it further away increases the energy of our system. And nature tends to take the lowest energy state. So that's exactly why when we look at the principal quantum numbers as our principal quantum numbers increase as we go from n equals one to n equals two to n equals three, or from Orbital S P to D. Our energy will increase as we go down this table. So now let's talk about electron configuration. Electron configuration is simply a systematic approach to representing and showing exactly where our electrons are placed within any given atom. In other words, in which shells or in which subshells are our electrons down? |
Aufbau Principle and Electron Configuration .txt | So now let's talk about electron configuration. Electron configuration is simply a systematic approach to representing and showing exactly where our electrons are placed within any given atom. In other words, in which shells or in which subshells are our electrons down? So let's look at the simplest atom. The h atom. The H Atom has one proton and one electron. |
Aufbau Principle and Electron Configuration .txt | So let's look at the simplest atom. The h atom. The H Atom has one proton and one electron. The proton is the nucleus. The electron is down, orbiting our nucleus. Now, what are the Quantum numbers of this electron? |
Aufbau Principle and Electron Configuration .txt | The proton is the nucleus. The electron is down, orbiting our nucleus. Now, what are the Quantum numbers of this electron? Well, this guy has the first principal level. The first principal quantum number, or N equals one. And that means if N equals one, our second quantum number, our L must be zero. |
Aufbau Principle and Electron Configuration .txt | Well, this guy has the first principal level. The first principal quantum number, or N equals one. And that means if N equals one, our second quantum number, our L must be zero. And if l is zero, that means our third quantum number, the orbital in which our electron is located is the s orbital. So to represent this in an electron configuration way, we simply do the following. We put a coefficient in front of our S. So the Wand represents our shell, our principal quantum number. |
Aufbau Principle and Electron Configuration .txt | And if l is zero, that means our third quantum number, the orbital in which our electron is located is the s orbital. So to represent this in an electron configuration way, we simply do the following. We put a coefficient in front of our S. So the Wand represents our shell, our principal quantum number. Our S represents our subshell. And at the same time, it also represents our orbital in which our electron is in. The SuperScript of one represents the number of electrons. |
Aufbau Principle and Electron Configuration .txt | Our S represents our subshell. And at the same time, it also represents our orbital in which our electron is in. The SuperScript of one represents the number of electrons. So we have one electron. So we have a SuperScript of one. So this Is The Electron Configuration for this atom. |
Aufbau Principle and Electron Configuration .txt | So we have one electron. So we have a SuperScript of one. So this Is The Electron Configuration for this atom. For the h atom. Now, any atom or any element on the periodic table has an electron configuration. So let's look at another one. |
Aufbau Principle and Electron Configuration .txt | For the h atom. Now, any atom or any element on the periodic table has an electron configuration. So let's look at another one. Let's look at oxygen. Oxygen has an atomic number of eight. And that means in its neutral state, it has eight electrons. |
Aufbau Principle and Electron Configuration .txt | Let's look at oxygen. Oxygen has an atomic number of eight. And that means in its neutral state, it has eight electrons. So let's look at its electron configuration. Now, notice that n equals One. It could fit two electrons. |
Aufbau Principle and Electron Configuration .txt | So let's look at its electron configuration. Now, notice that n equals One. It could fit two electrons. Because when n equals one, our l equals zero. And we only have one orbital, the S orbital. So we can place the maximum of two electrons into any orbital. |
Aufbau Principle and Electron Configuration .txt | Because when n equals one, our l equals zero. And we only have one orbital, the S orbital. So we can place the maximum of two electrons into any orbital. So we can place two electrons into shell level. N equals one. How about N equals two? |
Aufbau Principle and Electron Configuration .txt | So we can place two electrons into shell level. N equals one. How about N equals two? Well, n equals two has a maximum of two to the two. So maximum of four orbitals. That means if we have four orbitals, I have an s orbital and three p orbitals. |
Aufbau Principle and Electron Configuration .txt | Well, n equals two has a maximum of two to the two. So maximum of four orbitals. That means if we have four orbitals, I have an s orbital and three p orbitals. Right? So I could put a maximum of eight electrons into my N equals two energy level into my N equals two shell. So I place two electrons into my s orbital. |
Aufbau Principle and Electron Configuration .txt | Right? So I could put a maximum of eight electrons into my N equals two energy level into my N equals two shell. So I place two electrons into my s orbital. This guy's my s orbital. And then I could put six electrons into my three p orbitals. So 1234, I put Four, because I only have four left over. |
Aufbau Principle and Electron Configuration .txt | This guy's my s orbital. And then I could put six electrons into my three p orbitals. So 1234, I put Four, because I only have four left over. So now let's look at the electron configuration for our oxygen. In our principal quantum number one. N equals one. |
Aufbau Principle and Electron Configuration .txt | So now let's look at the electron configuration for our oxygen. In our principal quantum number one. N equals one. We have only the X orbital. So we place two electrons here. So one s, two. |
Aufbau Principle and Electron Configuration .txt | We have only the X orbital. So we place two electrons here. So one s, two. And now N equals two. We have an S and the three P's. And that means we first place two electrons into our S.
So two F, two. |
Aufbau Principle and Electron Configuration .txt | And now N equals two. We have an S and the three P's. And that means we first place two electrons into our S.
So two F, two. And then we distribute electrons into our piece. And we have three P's. So we start by putting one in each. |
Aufbau Principle and Electron Configuration .txt | And then we distribute electrons into our piece. And we have three P's. So we start by putting one in each. And I'll explain in a little bit why we put one here, one here, one here, and then one here. And not two here and two here and none here. I'll explain why in a second. |
Aufbau Principle and Electron Configuration .txt | And I'll explain in a little bit why we put one here, one here, one here, and then one here. And not two here and two here and none here. I'll explain why in a second. Now, so I place one here, one here, one here, and then I place my fourth one into my X. So we can also represent this guy in the following way. We simply erase all these X's as ZS and simply say two P and we place a four on top. |
Aufbau Principle and Electron Configuration .txt | Now, so I place one here, one here, one here, and then I place my fourth one into my X. So we can also represent this guy in the following way. We simply erase all these X's as ZS and simply say two P and we place a four on top. Now, whenever we do this, we make the assumption that you understand the fact that this is not a single orbital but this is actually three orbitals. Because if this was a single orbital, the four would not make sense because you could only place the maximum of two electrons into any orbital according to the Pole Exclusion Principle. So that's the electron configuration. |
Aufbau Principle and Electron Configuration .txt | Now, whenever we do this, we make the assumption that you understand the fact that this is not a single orbital but this is actually three orbitals. Because if this was a single orbital, the four would not make sense because you could only place the maximum of two electrons into any orbital according to the Pole Exclusion Principle. So that's the electron configuration. One. F two. Two. |
Aufbau Principle and Electron Configuration .txt | One. F two. Two. F two. Two. P four. |
Aufbau Principle and Electron Configuration .txt | F two. Two. P four. Since oxygen has a maximum of eight electrons, that means two plus two plus four eight electrons. So this makes sense. So every atom on the table, every element has its own electron configuration. |
Aufbau Principle and Electron Configuration .txt | Since oxygen has a maximum of eight electrons, that means two plus two plus four eight electrons. So this makes sense. So every atom on the table, every element has its own electron configuration. Now, let's look at sodium. Sodium has the following electron configuration, right? It has eleven electrons in its neutral state. |
Aufbau Principle and Electron Configuration .txt | Now, let's look at sodium. Sodium has the following electron configuration, right? It has eleven electrons in its neutral state. How about neon? Neon has ten electrons. It has a perfect configuration. |
Aufbau Principle and Electron Configuration .txt | How about neon? Neon has ten electrons. It has a perfect configuration. Every single orbital is completely filled. And remember, every atom on a table wants to become a noble gas. So every atom wants to become or wants to take the electron configuration of a noble gas. |
Aufbau Principle and Electron Configuration .txt | Every single orbital is completely filled. And remember, every atom on a table wants to become a noble gas. So every atom wants to become or wants to take the electron configuration of a noble gas. And Neon is, in fact, a noble gas. Another way representing electro configurations are using noble gas configurations. Notice that one S, two, two S two and two P, six is identical to one S Two, two S two and two P six of Neon. |
Aufbau Principle and Electron Configuration .txt | And Neon is, in fact, a noble gas. Another way representing electro configurations are using noble gas configurations. Notice that one S, two, two S two and two P, six is identical to one S Two, two S two and two P six of Neon. So we can replace this whole guy simply with neon. And these brackets simply mean the electron configuration of Neon. And then we add this guy three S one. |
Aufbau Principle and Electron Configuration .txt | So we can replace this whole guy simply with neon. And these brackets simply mean the electron configuration of Neon. And then we add this guy three S one. And this means this is the electron configuration of our sodium, right? Because sodium has one more electron than neon. That electron goes into the three S one energy level. |
Aufbau Principle and Electron Configuration .txt | And this means this is the electron configuration of our sodium, right? Because sodium has one more electron than neon. That electron goes into the three S one energy level. Now, the ground state of any atom represents its lowest energy state. This is the ground state of sodium. This is the ground state of hydrogen, and this is the ground state of oxygen. |
Aufbau Principle and Electron Configuration .txt | Now, the ground state of any atom represents its lowest energy state. This is the ground state of sodium. This is the ground state of hydrogen, and this is the ground state of oxygen. Now, when atoms go from a ground state to an excited state, what that means is they form ions or they form excited state atoms. And that simply means electrons jump to a higher state. And we'll talk more about that when we'll talk about the photoelectric effect. |
Aufbau Principle and Electron Configuration .txt | Now, when atoms go from a ground state to an excited state, what that means is they form ions or they form excited state atoms. And that simply means electrons jump to a higher state. And we'll talk more about that when we'll talk about the photoelectric effect. So one important aspect of electron configuration must be understood. Electron configuration doesn't necessarily have to order things from lowest energy to highest energy. Although that's usually the case, that doesn't have to happen. |
Aufbau Principle and Electron Configuration .txt | So one important aspect of electron configuration must be understood. Electron configuration doesn't necessarily have to order things from lowest energy to highest energy. Although that's usually the case, that doesn't have to happen. In other words, let's look at the following important facts. So four S that energy level is at a lower energy than three D, and five S is at a lower energy level than four D.
And this holds for six S and 5D as well. Now, these things you just have to simply remember. |
Aufbau Principle and Electron Configuration .txt | In other words, let's look at the following important facts. So four S that energy level is at a lower energy than three D, and five S is at a lower energy level than four D.
And this holds for six S and 5D as well. Now, these things you just have to simply remember. Now, if we look at the electron configuration for Bromine, which has 35 35 protons and 35 electrons, we see the following electron configuration. Now, this guy makes sense because one S comes before two S and two S comes before two P and two P comes before three S, and three S comes before three P. In other words, this goes from lowest energy level to highest energy level. And since we just said that four S is at a lower energy level than 3D, it would make sense to place the four S two before the this would be the correct election configuration if you're actually ordering from lowest energy level to highest energy level. |
Aufbau Principle and Electron Configuration .txt | Now, if we look at the electron configuration for Bromine, which has 35 35 protons and 35 electrons, we see the following electron configuration. Now, this guy makes sense because one S comes before two S and two S comes before two P and two P comes before three S, and three S comes before three P. In other words, this goes from lowest energy level to highest energy level. And since we just said that four S is at a lower energy level than 3D, it would make sense to place the four S two before the this would be the correct election configuration if you're actually ordering from lowest energy level to highest energy level. But this doesn't have to be the case. In other words, if I flip these guys, that isn't wrong. That's allowed. |
Aufbau Principle and Electron Configuration .txt | But this doesn't have to be the case. In other words, if I flip these guys, that isn't wrong. That's allowed. That's allowed to happen. And that's because electron configuration doesn't necessitate that you have to order them from lowest energy to highest energy. Although, if in a question and asks you for the proper electron configuration that order things from lowest to highest, then that has to happen. |
Aufbau Principle and Electron Configuration .txt | That's allowed to happen. And that's because electron configuration doesn't necessitate that you have to order them from lowest energy to highest energy. Although, if in a question and asks you for the proper electron configuration that order things from lowest to highest, then that has to happen. Then this is the proper electron configuration. So ions also can be represented using electron configuration. For example, let's look at sodium plus has eleven protons and ten elections. |
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