Skip to main content
Loading Explore guides…
Periodic Trends · Acedra
Home
Explore
Chemistry
Periodic Trends
Sign in to save
Chat
If YouTube asks you to sign in, open the video on YouTube.
Watch on YouTube
Reload player
Transcript
280 segments
Copy
Hide video
0:01
Kristen Merritt: Okay, so this lecture will be on periodic trends and it should be. I'm all in one lecture, hopefully won't be too long.
0:17
Kristen Merritt: So we're in intro you talk we talk about the periodic trends of atomic size or atomic radius increasing
0:26
Kristen Merritt: To the left and going down or conversely in decreasing as you go to the right and we go up. So look at fluorine, helium, hydrogen, though the smallest
0:38
Kristen Merritt: We're going to go a little deeper now into
0:43
Kristen Merritt: How atomic size is affected, we have something called Z Effective. Z, If you remember, is the proton, the number of protons, which is going to be the number of positive charges. Right. So Z effective, however, is the outer electrons do not feel the full force of the protons in the nucleus.
1:04
Kristen Merritt: They are shielded
1:07
Kristen Merritt: By
1:09
Kristen Merritt: The electrons between the electrons and the nucleus, all those inner shells and sub shells and also a little bit by the other electrons in the same shall
1:22
Kristen Merritt: We also have something called ionization energies which is the energy required to remove an electron. And this is plural. Kristen Merritt: Because we have first ionization energy second ionization. Third, etc. And it's the removal of the first electron, the second electron, the third electron and how, what does are in relation to the first depends on
1:44
Kristen Merritt: Where the the element is in the periodic table, and what the orbital or molecular configuration is excuse me electron configuration is
1:55
Kristen Merritt: Acid removal of the first or the second. In other words, if it's at a stable place after let's say removal of two electrons like magnesium Kristen Merritt: You remove two electrons from magnesium is magnesium ions and it has a noble gas configuration. So the third ionization energy. The removal of the third electron would be really high because
2:17
Kristen Merritt: It doesn't want any more electrons removed. It's a perfect situation full shells doesn't want to receive or remove any electrons. So that's the logic behind ionization energies electron affinity is just like the word says the affinity towards the desire to have an electron. So
2:36
Kristen Merritt: If the affinity is high.
2:40
Kristen Merritt: Then that means it has a great desire or affinity for the electron. And that means that once the electron is added, for example, with fluorine. When you add one electron. Kristen Merritt: It gets the noble gas configuration, therefore, that is a lower energy level. The resulting fluoride ion is at a lower energy level.
3:04
Kristen Merritt: And so the energy that between the two stages is released, if, if I'm going to a lower energy level, something has to happen with that energy that the fluoride. Fluoride had it's released Kristen Merritt: So we're going to go into all that. So that's called a higher affinity, a lot of energy is released a low affinity either a little energies released or you actually had to put energy into force it to happen.
3:27
Kristen Merritt: Okay, that's the general statement. So we talk about
3:34
Kristen Merritt: Energy everything in chemistry is energy literally everything. So some of the forces involved.
3:45
Kristen Merritt: So we still have cool arms law and the force of proportional to
3:52
Kristen Merritt: The Sun the charges multiply times each other and inverse related to the radius, the distance. Okay, so an electron
4:06
Kristen Merritt: Exists in a particular orbital, that is an energy level that is determined by the energy level of that electron. What is that energy level determined by. It is a combination of factors, but some of the factors are
4:22
Kristen Merritt: The charge the positive charge.
4:26
Kristen Merritt: In the nucleus. So, the greater the positive charge, the greater number of protons, the greater your force will be. And this is the electron charge inverse related to the distance
4:38
Kristen Merritt: But you also have repulsion effect of this of the electrons.
4:43
Kristen Merritt: Between your electronic question and the nucleus. So perhaps it's it's Iodine is a really large Adam
4:53
Kristen Merritt: So the electron which on the one the valence electrons, its way out here and there's lots of electrons. A lot of shells and sub shells and orbitals between that electron and the nucleus.
5:05
Kristen Merritt: So you have a really large are, but you also have this other aspect of the other electrons around so you have repulsion from that electron and the ones between it. You also have repulsion from that electron and the others.
5:20
Kristen Merritt: In the same sub shell shell is S is this up. Show P is a sub show and the socials are broken up into orbitals, as only has one orbital.
5:33
Kristen Merritt: So the s orbital has two electrons. It's a single orbital but P can have six electrons. So it's three orbitals.
5:50
Kristen Merritt: And the interaction of the all of those electrons can also have an effect on the energy level of the electron.
5:56
Kristen Merritt: Just some terms here, the inner core. The inner electrons are the core electrons are the non valence electrons.
6:04
Kristen Merritt: The outer electrons are the highest energy level, the highest in that means
6:10
Kristen Merritt: If I am in period for me gets my periodic table.
6:16
Kristen Merritt: 1234 my outer electrons know what else, what valence. We're talking about the outer different term but related does not include the three unless the three is still being filled
6:31
Kristen Merritt: But once I filled the 3D. Let's say I'm looking at selenium over here.
6:36
Kristen Merritt: This is now an inner core. This is part of the inner electrons. Because remember, as soon as you start adding electrons to the D. Kristen Merritt: The energy level drops it is now lower than the ass. So for S. So let's say we're talking about selenium for us and for P sub shells are your outer electrons. The D. Once it's filled becomes inner
7:05
Kristen Merritt: Okay.
7:08
Kristen Merritt: So we have your so your end number determines outer versus enter and where you are, what what show you're talking about. So that's just terminology
7:21
Kristen Merritt: So the factors again affecting the energy you have the nuclear charge you have what we call shielding by the other electrons.
7:32
Kristen Merritt: Primarily from the ones between the electronic we're talking about and the and the nucleus. All those in between. Kristen Merritt: And the orbital shape which I'm really not going to go into because that's taking it to another level that we don't know going to right now, so be concerned about the shielding and the nuclear charge.
7:51
Kristen Merritt: The shielding. What that does is we take the nuclear charge.
7:57
Kristen Merritt: So z for. Let's go back to my periodic table.
8:04
Kristen Merritt: So the Z is the number of protons.
8:07
Kristen Merritt: So the Z for magnesium is 12
8:11
Kristen Merritt: The z for barium is 56 the Z for this month is at three, however.
8:17
Kristen Merritt: This month is really far away from the nucleus. And it has all of these shells between it and the nucleus. It does not feel the outer electrons of business do not feel the full 83 proton charge
8:33
Kristen Merritt: Is diluted in a sense it's shielded so what it does feel and as a way of calculating this we call it the Z Effective z.
8:42
Kristen Merritt: It's what it actually feels it's the effective nuclear charge.
8:48
Kristen Merritt: And in lab three
8:50
Kristen Merritt: Or love to. I think one of your laps. You're going to be calculating this and graphing this
8:57
Kristen Merritt: So sub levels. The book talks about sub levels. I call this sub shells. So, s, p, d. These are sub shells within your sub shells, you have the orbitals.
9:14
Kristen Merritt: So your assumptions become more stable, the closer they are to the nucleus. Makes sense, they can feel the attraction the proton charge greater the further out you are, the less you can feel it. The lower the energy
9:30
Kristen Merritt: So your outer electrons are those sub shells are least stable because they're for out and they're easier to remove
9:40
Kristen Merritt: The closer to the nucleus, you get the more those electrons feel that proton positive charge or multiple paths charges and the harder it is for movie. Let's try it makes sense. Think of a really strong magnet and a really weak magnet.
9:57
Kristen Merritt: When we have when we take into effect all of the electrons involved, you have some shielding because of the other electrons in the same sub show
10:10
Kristen Merritt: That repulsion.
10:12
Kristen Merritt: With each other.
10:15
Kristen Merritt: So in a p
10:19
Kristen Merritt: sub shell. For example, let's look at arsenic here arsenic has three electrons in this in the P sub show one of these are orbital. Kristen Merritt: Those three electrons are going to have repulsion effect on each other and they're going to be selling the other ones get this guy out of here.
10:35
Kristen Merritt: So these electrons will be easier to remove. You're not only farther from the nucleus and they have all of these electrons between, let's talk about this electron right here and the nucleus. You also have this electron
10:50
Kristen Merritt: With repulsion effect from this one and this one. So that's going to increase the chance of your ability to remove it. It's going to take less energy to remove that electron
11:01
Kristen Merritt: But the greater effect is the shielding from the core electrons all of yourself show electrons so says kind of common sense.
11:13
Kristen Merritt: So, because of this z effective the effective charged and effective nuclear charge. How strongly does the electronic question field. The poll from the center
11:25
Kristen Merritt: contributes to the atomic size.
11:29
Kristen Merritt: So again, when we look at the periodic table because this is periodic trends as we go to the right, the radius gets smaller.
11:38
Kristen Merritt: Because when you're in the same period, particularly the first
11:43
Kristen Merritt: Three. There are no other you're not adding other inner electrons like the transition metals here.
11:51
Kristen Merritt: So these are all in the same shell.
11:54
Kristen Merritt: So you're not adding any underneath a core electrons are all outer electrons. Kristen Merritt: And every time you add an electron, you're also adding approach on every step forward as an increasing approach is you're increasing your proton charge Kristen Merritt: You're not adding any core electrons. And so all of these electrons are being brought in tighter because they have a greater z effective to get to our GM
12:17
Kristen Merritt: So as you go to the right.
12:21
Kristen Merritt: Your radius decreases your out of the smaller
12:24
Kristen Merritt: As you go down, it increases because of course we're adding all of these extra electrons member these shells are nested within each other. Kristen Merritt: So even though we're not using the ball of concentric circle. It's still a nesting. It's just a shape is very different. We have some shells and orbitals. And these things.
12:44
Kristen Merritt: But you're still putting a huge number of electrons between your outer electrons plus it were inseparable. This will be our best month. Again, we'll talk about this electron
12:58
Kristen Merritt: As all of these shells full electron between it.
13:03
Kristen Merritt: And the nucleus. So the Z if is much less and it's able to be held more loosely. So it's going to expand more Kristen Merritt: It's not held as tightly because it's not hold feeling the fall at three charts. And again, you'll be calculating what that actually is. It feels so that's how the Z Effective contributes to the atomic radius.
13:28
Kristen Merritt: The trend is still the same that you learned an intro
13:31
Kristen Merritt: Decreases to the right. It's smaller increases as you go down. So we're getting bigger, as we go down here.
13:39
Kristen Merritt: And here's a
13:42
Kristen Merritt: General representation. And you can see over here with groups wanted to the differences sizes more noticeable.
13:50
Kristen Merritt: Then as you go further rights.
13:54
Kristen Merritt: Because there's there's these still can feel
13:59
Kristen Merritt: The proton charge
14:01
Kristen Merritt: Greater
14:03
Kristen Merritt: And you don't have the repulsion.
14:06
Kristen Merritt: Effect that you do over here. We just keeping them away from each other. So
14:11
Kristen Merritt: But you still can see the general trend of size that's that's the point of this
14:16
Kristen Merritt: We are decreasing as we go this way. So even though we're increasing down, it's still. These guys are going to be smaller than these guys.
14:27
Kristen Merritt: So what are we going to rank elements.
14:31
Kristen Merritt: No I OS or anything. Just elements right now and decrease atomic size you're going to go according to periodic table. So we have calcium, magnesium and strontium Kristen Merritt: Here's calcium here here's magnesium here in his strontium, so obviously the magnesium will be smaller than the calcium, which is smaller the strontium
14:54
Kristen Merritt: Or you can say at the reverse way strontium is larger than calcium, which is larger than magnesium so that follows the trend going down a group. The next is potassium. I don't know what GA is gallium, I think.
15:09
Kristen Merritt: And calcium. So here's potassium and here's calcium and here is it is gallium. So this is going to be the trend going along a period Kristen Merritt: Is smaller to the right. So gallium is going to be smaller than calcium, which is smaller than potassium. And in fact, here's potassium here here's calcium here and here's gallium here so you can see that
15:31
Kristen Merritt: And then there's your trend. So it's that's going across a period rubidium bro mine and Krypton.
15:40
Kristen Merritt: Well here's Krypton here's
15:43
Kristen Merritt: Bromine
15:47
Kristen Merritt: Bromine rubidium and Krypton. Here's Krypton. Here's bromine.
15:53
Kristen Merritt: And where's rubidium
15:56
Kristen Merritt: There's rubidium way over here. So we're video is going to be the largest it's not only further left. It's down the next period. Kristen Merritt: So it's further left and at a lower at a higher period, a greater end number, the greater your end number. The further you are from the nucleus. That's what it means, one of the things Kristen Merritt: So that's going to be larger. And then we're going to go bromine and Krypton because now we're going trend to the right.
16:24
Kristen Merritt: Right. And then there are your explanations.
16:28
Kristen Merritt: Okay, what if we look at nitrogen, phosphorus, oxygen and so far.
16:33
Kristen Merritt: You're looking for the smallest atomic radius. So here's nitrogen, oxygen, phosphorus and sulfur.
16:40
Kristen Merritt: Excuse me, I to sneeze.
16:44
Kristen Merritt: Pardon me.
16:45
Kristen Merritt: Okay, well, the ones at the higher period are going to be bigger.
16:51
Kristen Merritt: Than the true on the smaller period than a period to so period three items are going to be bigger than period to
16:57
Kristen Merritt: So we're going to eliminate phosphorus and sulfur. That leaves, nitrogen, oxygen,
17:02
Kristen Merritt: Well, we got to go to the right you can smell some oxygen is the smallest following that logic. So, the answer would be oxygen.
17:12
Kristen Merritt: Alright, so that's size ionization energy is the energy required to remove an electron. And it's officially
17:21
Kristen Merritt: It's official definition is the complete removal. So, it is completely out of the area of being influenced by the nucleus is remember there are infinite Kristen Merritt: Energy levels for an electron to be excited to. So this has to actually be removed far enough that it has no feels no more influence of the nucleus. So complete removal of one mole of electrons fun one from one mole of gaseous Adam, or I on. So that's the official definition.
17:54
Kristen Merritt: Obviously Adams with a low ionization energy, which means it takes very little energy to remove electron from cat is makes sense. That's why they form cat is enter Adams with a high ionization energy. It takes a lot of energy to remove the electronic form as a rule form and eyes.
18:16
Kristen Merritt: And the energies decrease down a group because we're getting bigger, the larger your Adam gets the easier it is to remove and electron because it's feeling the effective Kristen Merritt: Charge of the nucleus less and less and less. So these are easier to remove than this. And the other trend is it increases across a period because, of course, we go across a period
18:41
Kristen Merritt: Your element is getting smaller. So it's going to feel the force of the of the nucleus. The protons nucleus more but also as we go closer to the right.
18:54
Kristen Merritt: The addition of electrons will contribute to the formation of a noble gas status. So there's
19:04
Kristen Merritt: You know if I like to talk about these in human terms, it doesn't want to have Adams electrons removed it wants to have them added so it can become noble gas data. So there's some logic to it there.
19:16
Kristen Merritt: There is a very interesting trend. Notice
19:20
Kristen Merritt: So hydrogen know we're just gonna hydrogen lithium 520
19:28
Kristen Merritt: Kilojoules promote
19:30
Kristen Merritt: To remove an electron, because it removes one and it's at
19:36
Kristen Merritt: Noble gas status. So that's a that's considered a low ionization energy beryllium is higher.
19:44
Kristen Merritt: But once you get past this is a field s shell now boron. It's actually a little bit lower energy because once you remove one electron from boron.
19:55
Kristen Merritt: You have a field shell state.
20:00
Kristen Merritt: So the trends also follow the stability of what happens when the electron is removed.
20:06
Kristen Merritt: So as we go up. This is the p orbital. So here's boron copper, nitrogen, oxygen flooring.
20:15
Kristen Merritt: Well as we go up the first three
20:19
Kristen Merritt: Orbitals
20:21
Kristen Merritt: Of the P shell sub show
20:24
Kristen Merritt: Your organization ionization energy increases, right, it's getting harder and harder.
20:31
Kristen Merritt: To remove an electron as your element gets smaller, however, look at this between nitrogen and oxygen.
20:37
Kristen Merritt: All of a sudden, it's easier to remove an electric from oxygen then from nitrogen why. Let's go to the whiteboard and I'll show you.
20:52
Kristen Merritt: And it has to do with the stability.
20:55
Kristen Merritt: Of
20:58
Kristen Merritt: What of your element. After you've removed that electron. So nitrogen is
21:07
Kristen Merritt: One es tu tu es tu
21:11
Kristen Merritt: Tu P3 and oxygen is one es tu tu es tu tu P for. So I'm going to skip the, the one has to right now I'm just going to talk about the valence electrons.
21:23
Kristen Merritt: So there's my two s orbit orbital.
21:27
Kristen Merritt: This is the orbital configuration. And here are my two p. Here's each orbital.
21:34
Kristen Merritt: Okay, so we label the bottom of it.
21:38
Kristen Merritt: Both of these have the filled, that's not gonna work.
21:44
Kristen Merritt: Filled s
21:47
Kristen Merritt: Now nitrogen we enter one electron in each empty orbital.
21:55
Kristen Merritt: That's the lowest energy configuration. Now he remember I have filled sub shell is stable.
22:03
Kristen Merritt: The next more stable or the more stable configuration from this is a full filled sub show. So this is the next most stable configuration.
22:16
Kristen Merritt: No oxygen.
22:19
Kristen Merritt: Is to pee for. So now we're going to start doubling up there's oxygen.
22:25
Kristen Merritt: When I remove this electron from oxygen.
22:29
Kristen Merritt: The result.
22:31
Kristen Merritt: Is the half filled shell and that's more stable. That's why the energy, the ionization energy.
22:39
Kristen Merritt: For oxygen is lower than for nitrogen, because the result is a more stable configuration. And you can see this trend.
22:52
Kristen Merritt: Throughout
22:55
Kristen Merritt: You know, you see it again with the phosphorus
22:59
Kristen Merritt: And then energy drops back down for sulfur. So it's easy to remove the electron from self within from phosphorus
23:05
Kristen Merritt: It's a little more confusing when we add the
23:09
Kristen Merritt: The F.
23:12
Kristen Merritt: Into transition
23:15
Kristen Merritt: Melt metal. So let's just stick to the first few periods for this trend, but it's definitely there.
23:22
Kristen Merritt: And this is
23:25
Kristen Merritt: This slide shows it. So this is ionization energies, there's helium.
23:31
Kristen Merritt: Helium, of course, is a noble gas configuration. So it would be very hard to remove an electron from that. So it's a high ionization energy. You have to put down much energy into it to remove an electron Kristen Merritt: But now we go back down. Here's lithium, or if lithium removes one electron, it has this configuration. So it's a very low ionization energy.
23:52
Kristen Merritt: And this is beryllium.
23:55
Kristen Merritt: It's a little harder to remove this because it only gives you the lithium configuration is preferred. But it's still, it's still pretty low.
24:03
Kristen Merritt: That's considered low. Now we start with the P sub shell.
24:08
Kristen Merritt: So this is boron.
24:11
Kristen Merritt: And it drops back down. Because again, if you lose one electron from boron, you get a filled shell configuration that stable.
24:19
Kristen Merritt: There's carbon. Here's nitrogen. Here's your oxygen dip because losing this electron will give you the nitrogen configuration of a half filled sub show
24:29
Kristen Merritt: half filled P sub shell. And then, of course, the closer we get to the noble gas configuration, the higher your ionization energy goes. This is first ionization energy removal of one electron.
24:41
Kristen Merritt: We start a new and number a new period. And once again, it just breaks down because removing one electron will give each of these a noble gas configuration. And sure enough, we see lithium, sodium, potassium, etc with general exist as a one plus, can I am
25:00
Kristen Merritt: So this trend follows along it gets a little messier. When we get into the D added the orbitals and add the F. So, recognize it more for the first three periods, but
25:13
Kristen Merritt: You always want to look at when you're wondering what will be the energy to take this action with an atom with you're adding electron or removing electron or removing two electrons, look at the result. What will it give me. Well, it gives me a more stable.
25:30
Kristen Merritt: Situation if it will give a more stable. Stable situation is going to be a lower either a lower energy needed to remove that one or two electrons or a greater affinity to receive an electron. So you always want to look at what's the end result.
25:49
Kristen Merritt: So if we're going to rank and this we show a first time ization energy with a subset one second ionization energy would have a little too down here. So that's removal of the second electron, not two electrons. But the second we talked about each individual electron individually.
26:09
Kristen Merritt: So if we're going to rank these we have Krypton helium and argon.
26:14
Kristen Merritt: Here's Krypton.
26:17
Kristen Merritt: Helium all at the top. An Arbonne
26:20
Kristen Merritt: The larger your
26:23
Kristen Merritt: Element is the easier it is to remove and electron so Krypton will have a lower that are gone, which is lower than helium. Now, none of these are going to have low
26:37
Kristen Merritt: ionization energies, because they're all noble gases, but here's Krypton.
26:43
Kristen Merritt: Here's our gone and here's helium. So the larger you go look at how like here's xenon it's equivalent to it's actually lower than the oxygen here.
26:54
Kristen Merritt: Krypton looks like it's equivalent to between the Nitrogen, Oxygen ionization energy. So it really does make a difference. The size of the element makes a significant difference. I'm
27:09
Kristen Merritt: Tend to really them and I forget what SP is
27:13
Kristen Merritt: So here's 10
27:15
Kristen Merritt: Go back. What was that G Trillium n sp. Here's sp. Here's chin. Here's throwing. Okay, so these this is these three elements. And so as we go to the right, your ionization energy will increase.
27:34
Kristen Merritt: Now again, that trend I talked about with a half filled full that's more more in evidence in the first, you know, period, two, and three. Kristen Merritt: So it wouldn't really apply here because at this point, we have the d orbitals involved as well. So just keeping with a strict trend of going to the right 10 should be greater should be lower. Excuse me, then, antimony ventral delirium Hillary
28:06
Kristen Merritt: And that was not even listed here. But anyways, it would be just this this trend going the ionization energy increases as you go to the right.
28:17
Kristen Merritt: potassium, calcium and rubidium
28:20
Kristen Merritt: Potassium is here. Calcium is here and Rubidium is down here so Rubidium is
28:26
Kristen Merritt: Higher period number or a number and it's for the left. So that would have the lowest ionization energy. And then potassium and then calcium
28:45
Kristen Merritt: Oh, I think I said that backwards calcium has the highest ionization energy is further to the right.
28:53
Kristen Merritt: Potassium has an x is rubidium has the lowest ionization energy because it's larger and is for the simple act.
29:01
Kristen Merritt: Okay, iodine seen on and cesium
29:07
Kristen Merritt: There's xenon iodine.
29:11
Kristen Merritt: And where is cesium
29:22
Kristen Merritt: Okay, I know where it is, but I can't find it. Let's see what let's see what so I xenon obviously is going to have the higher
29:29
Kristen Merritt: Ionization energy is a noble gas is further to the right than iodine.
29:35
Kristen Merritt: And for some reason, I cannot find cesium
29:46
Kristen Merritt: Further to the left and a higher peer. So when you find cesium
29:54
Kristen Merritt: For this left in a higher period.
29:57
Kristen Merritt: Oh, that's why. Because it was
30:02
Kristen Merritt: Okay so cesium is here. So that is going to have the lowest ionization energy because it's at a higher period. So it's larger and us for this or the left. Then I then, as you know. All right.
30:15
Kristen Merritt: Um,
30:18
Kristen Merritt: Nitrogen, phosphorus, oxygen, sulfur, once again, we had that question for radius. And so the answer should be the opposite the lowest ionization energy means is easier to remove
30:30
Kristen Merritt: Nitrogen, Phosphorus cell for oxygen. It wouldn't be nitrogen, oxygen, because they're at a lower period number
30:39
Kristen Merritt: So of the sulfur and the phosphorus. The phosphorus is further left. And sure enough, it does have the lowest ionization energy. Whoops.
30:49
Kristen Merritt: Actually, no, that's not correct.
30:53
Kristen Merritt: So this is because this is in the third period. So this still follows that half filled
31:00
Kristen Merritt: Sub show
31:02
Kristen Merritt: And if you look, the sulfur is is that is lower than phosphorus
31:08
Kristen Merritt: Because when we move. Remove the electron from sulfur. We are left where they have Phil sub show which is more energetically favorable. So in this case, because of that rule. And we're still in the first three periods, the sulfur actually has the lower
31:27
Kristen Merritt: Ionization energy just a little bit because losing this will give you a more stable electron configuration.
31:36
Kristen Merritt: So there's an example to take your time. When you get these questions and think them through don't answer them too quickly, or you'll make mistakes like I just did.
31:49
Kristen Merritt: Yeah, that was common sense.
31:52
Kristen Merritt: So this is just shows you the trends of the ionization energies. And if you notice, whenever you have a full shells. So this is the first ionization energy. There's your second. There's your third etc. When you break into the core electrons.
32:10
Kristen Merritt: Which is the electron configuration of the inner electrons no longer the outer higher energy your ionization energy really jumps up. So this is when you're in disrupting a noble gas configuration.
32:24
Kristen Merritt: I'm UCLA, a huge leap and ionization energy. And it makes sense.
32:30
Kristen Merritt: So the largest jumping ionization energy for aluminum.
32:35
Kristen Merritt: Well, we know that aluminum exists as a three plus i on right so this is easy to remove. Because it gives you
32:43
Kristen Merritt: A filled shell but the fact that we know it exists as a three plus ion. Once you remove these two, you had a neon configuration.
32:55
Kristen Merritt: That's the one that's going to be hard to remove the fourth electron
33:05
Kristen Merritt: And if we look at this table aluminum is not on this table.
33:09
Kristen Merritt: But
33:12
Kristen Merritt: The largest jump would be between would be
33:17
Kristen Merritt: The fourth ionization energy removing the fourth electron
33:23
Kristen Merritt: So between the third and the fourth would be your biggest jump.
33:29
Kristen Merritt: Fourth ionization energy will be much much much much greater than the third and so that would be your leap. Okay.
33:40
Kristen Merritt: Opposite to ionization energy. You have electron affinity and it's just like it sounds, the affinity means it wants electrons. So this is the tendency to attract electrons. Again, the official definition is the energy change.
33:54
Kristen Merritt: When one mole of electrons is added to one mole of the gashes Adam, or I am
34:01
Kristen Merritt: With a low affinity means it does not want electrons. He doesn't want them. It tends to form cat items wants to give them up. Not take them. Kristen Merritt: high electron affinity means yes it does want electrons and they tend to form ions. So affinity is generally given with a positive or negative sign, and that refers to the energy
34:24
Kristen Merritt: Released or force ionization energy is always with a positive sign
34:31
Kristen Merritt: There is always energy required to remove an electron as sometimes it's very, very low and it's made up by the new situation.
34:41
Kristen Merritt: Electron affinity can be positive or negative. Because remember, here's flooring, the elements. Once you add an electron, see what Kristen Merritt: The result is a lower energy level within all the time in as a filled sub show when I say it's a lower energy level, where did that energy go. It was released just like you have the delta H for entropy
35:06
Kristen Merritt: Of a reaction XO thermal versus endemic a delta a negative delta. He is an excellent automatic reaction it is released, it's a product, the same
35:18
Kristen Merritt: Concept is here. If you have a negative EA
35:23
Kristen Merritt: energy is released. So you, the higher the negativity. A, the more energy is released. That means the more stable. The product is the, the end result, the greater the affinity. So it's a very logical thing. The trend is near not nearly as clear cut as for ionization energy.
35:42
Kristen Merritt: So you just have a general trend.
35:48
Kristen Merritt: So the general trend, but again for affinity. It's these angels, you're going to be given to answer. We're going to be really clear cut because there are a lot of exceptions to it's a bit more complicated, but in general.
36:03
Kristen Merritt: The smaller your Adam is your element, the greater because it's kind of feel the, the effect of charge more. Right. So, the greater the affinity Kristen Merritt: So as you go up the periodic table and to the right, which is fits with a smaller radius, the greater the affinity. Remember non metals prefer to be an eye on. So obviously, they would have a greater affinity that metals which tend to be cat ions.
36:28
Kristen Merritt: Your atomic size follows the same trend. This is written in reverse increases increases or you could reverse these arrows and say, just like this. Kristen Merritt: Your size decreases going up and decreases, going to the right gets smaller as you go to the right gets smaller as you go up the ionization energy is the opposite.
36:49
Kristen Merritt: The smaller your atom is, the harder it is to remove and electrons to the greater your ionization energy is the same, going to the right. So make sure you know these general trends.
37:01
Kristen Merritt: The last thing is ions.
37:04
Kristen Merritt: Now the size of an element follows that specific trend going up and going to the right of the periodic table, but the size of an eye on depends on how it got there. If you remove an electron
37:18
Kristen Merritt: It significantly decreases the size of that element if you add them electron is significantly increases.
37:26
Kristen Merritt: When the ions, if you remember produce
37:32
Kristen Merritt: Noble gas electron states was my periodic table. Here we go. So when you have the same electron state. For example, potassium, iron, calcium, plus Kristen Merritt: Is the same look from configuration is our God, we say that it is ISO electronic with Arbonne chloride ion. It added an electron, it is ISO electronic with argon. However, they do not have the same size.
38:00
Kristen Merritt: The chloride I on the Argonne element and the potassium ion all have the same configuration.
38:09
Kristen Merritt: But the chloride is going to be bigger.
38:12
Kristen Merritt: Than they are gone because it added so significantly increases the potassium is going to be much smaller because it significantly decreases when you said when you lose an electron. So the trend is
38:28
Kristen Merritt: When you have an ISO electronic series.
38:33
Kristen Merritt: And you're told to rank them by
38:37
Kristen Merritt: You know rank them by size. That means they have the same number of electrons. So anything that got there by losing electrons is going to be smaller and the more electrons you lose the smaller it is, the more electrons you add the bigger it is. So keep in mind that trend. Here's some examples.
38:57
Kristen Merritt: That show you just how significant this can be
39:01
Kristen Merritt: So the, the sodium element is 186 extremes, it loses one electron is 102
39:09
Kristen Merritt: Now, unfortunately, this doesn't show us a noble gas that would be nice if it did the flooring.
39:15
Kristen Merritt: Element is 72 is sorry is 72 extremes.
39:21
Kristen Merritt: When it adds an electron is 133
39:25
Kristen Merritt: So flooring is ISO electronic with sodium, but this is 133 Engstrom. This is 102 and yet they have the same number of electrons, the same configuration, the same field shells and sub shells.
39:42
Kristen Merritt: Because this this still has a greater number of protons. So it's going to pull in tighter.
39:48
Kristen Merritt: Than this aluminum.
39:51
Kristen Merritt: The element is 143 angles, it goes down to
39:57
Kristen Merritt: When it loses its three
40:00
Kristen Merritt: Electrons and yet it is ISO electronic with magnesium two plus sodium, but with all of all of these have the same electronic structure yet look at the differences in their size.
40:13
Kristen Merritt: So remember that trend that if your configuration got there from gaining electrons, the more gains the bigger it is the got there from losing electrons, the more it loses the smaller this
40:29
Kristen Merritt: So, for example, calcium strontium and magnesium. How would you rank these we have to look at the each last two electrons.
40:42
Kristen Merritt: Where's my periodic table.
40:45
Kristen Merritt: So calcium strontium magnesium
40:51
Kristen Merritt: They're all in the group. Choose a
40:55
Kristen Merritt: Director
41:01
Kristen Merritt: And they all lost two electrons.
41:06
Kristen Merritt: But strontium has more protons, doesn't it.
41:13
Kristen Merritt: But magnesium started out smaller to begin with. So your logic here is that each last two electrons. Therefore, you're going to follow the trend of the periodic table.
41:25
Kristen Merritt: Which means this the ion if they all have the same
41:29
Kristen Merritt: Last the same number of electrons. This is bigger than this, which is bigger than this because this still
41:37
Kristen Merritt: Has all these sub shelves behind it.
41:40
Kristen Merritt: So if you have lost the same number of electrons and you're the same group, you will follow the normal trends or the size trend.
41:51
Kristen Merritt: Is my questions. One more periodic table down here.
41:58
Kristen Merritt: So potassium sulfur and chloride. However, this last one electron. This game too. And this game one because
42:11
Kristen Merritt: So here's your potassium. So your potassium iodide, an eye on those are gone. I saw electronic with argon chloride I on our so electronic with are gone and sulfur sulfite is is is ELECTRONIC WHICH MEANS THE ONE THAT gained the most electrons sulfur is larger than fluoride, which is larger.
42:30
Kristen Merritt: Than potassium. Potassium is going to be pretty small.
42:38
Kristen Merritt: You see if that's if that's on here. So there's potassium is 138
42:46
Kristen Merritt: Chloride is 181 as offers 184 so there's not much difference between sulfide in Florida, but it still is there.
42:55
Kristen Merritt: And then gold one plus versus three plus the more electrons you lose the smaller
43:04
Kristen Merritt: Your radius is so gold loses one electron is going to be still larger than gold losing three electrons. Again, that's kind of common sense.
43:17
Kristen Merritt: Okay, so those are the trends, the periodic table. A lot of is just really common sense. Again, think about, especially when you're looking at electron affinity and ISO ionization energies flow. Kristen Merritt: Look at the result and then determine, is it more stable. Like, what does it do to the stability and that will help you determine the level of affinity or the level of the ionization energy.
43:46
Kristen Merritt: Okay.
Here to help you learn
Sign in to keep a private conversation with your course tutor.
Ask me anything about the material…
Sign in to chat