00:02
In this video, we're going to be looking at loose structures and specifically looking at making sure that they are following their resonance kind of structure when applicable.
00:13
And basically what resonance is meaning is that they're going to just make their correct configuration as best as possible.
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And so we're going to show those resonances with these if we need to on each of these.
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So i'm just going to go through each of these steps.
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We're going to look at the first one, which is no2 minus.
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When we're looking at this, we want to make sure it follows the octet rule.
00:35
And also we're going to show formal charges on these as well.
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And so we're going to follow the same procedure.
00:42
We're going to count how many valence electrons we have and place that in our lewis structure.
00:48
So we have nitrogen we know has five valence electrons.
00:52
So five plus our two oxygens that carry six each.
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So we're just going to add that as 12.
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And then we have this formal charge right here, negative 1.
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We're going to add those, that one extra electron into this valence as well.
01:08
So we have 12 plus 6 pretty much, making a total of 18 valence electrons that we need to include in this structure.
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So we have our nitrogen.
01:17
We have our two oxygens here.
01:20
Okay.
01:21
And so we've used up four valence electrons.
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We're going to subtract that from that there.
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So making a total 14 left.
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One, two, three, four.
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5, 6, 7, 8, 9, 10, 11, 12, 13, 14.
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So we've got our 14 valence electrons here.
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We're going to make that now zero.
01:40
And now we're going to look and see, okay, does it follow the octet rule? if it doesn't, let's try and make it follow the octet rule.
01:45
And then let's make sure it follows and it meets the formal charges there as well.
01:53
Okay, so when we're looking at this, we know our oxygens, if we looked at it, these do follow the octet rule here.
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Nitrogen, however, does not.
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It's not following that octet rule, and so we need to kind of fix that.
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Right now, it's at 1, 2, 3, 4, 5, 6.
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So it needs two more, and so what we could do is we could create a double bond right here.
02:15
So we could use these, donate those, to make a double bond.
02:19
And when we do that, this is going to be our new configuration that i'm going to draw over here.
02:25
So we have our oxygen, double bonded to our nitrogen.
02:30
It still has two valence electrons right there, two free -floating electrons, i should say.
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And then we got that.
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Let's see if it still follows it.
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So 1, 2, 3, 4, 6, 7, 8.
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So we're still following the octet rule for each of these.
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Nitrogen, 1, 2, 3, 4, 6, 7, 8.
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So now we're following that octet rule.
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Now let's see how it looks for our formal charges in this structure.
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And so right here we have our oxygen.
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Remember, oxygen starts with 6 valence.
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Electrons, we're going to subtract the free floating electrons, which is four.
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And then we're going to subtract half of the bonded.
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So we're going to subtract two.
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Since there's a total of four, but we can only take half of those.
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When we do that, it's now got a, this has got a zero formal charge.
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Let's look at nitrogen.
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Nitrogen, we know starts with five.
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We have two minus three.
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So that's got a zero formal charge as well.
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And then we have our oxygen right here that when we figure it all out, 6 minus 6 minus 1, it's going to have a negative 1 formal charge.
03:38
So right here, it's looking pretty dang good because we have most of the bonds or most of the atoms are going to have a zero formal charge.
03:48
And then we have a negative 1 formal charge on one of these oxygens that has, that obviously is the most electron.
03:57
Negative and so we would want that negative on an oxygen rather than a nitrogen.
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The thing is that we can see here is this double bond could have been right here or it could have been on this oxygen.
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And so what we're going to do is show resonant structures on this one.
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And so there's two ways you could draw this.
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Here's the one way that we just did right here.
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And we know it's got a negative one formal charge, but also it could be drawn as such as well.
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So right here is the completed answer.
04:50
We've now drawn, we've shown resonance here, showing that it could be in this format or this format does not matter.
04:59
But anyways, there's that.
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So that's what we're going to kind of be looking at when we go through each one of these.
05:03
So we just did that one.
05:04
Let's look at no3 negative.
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So we have no3 negative.
05:10
So we have nitrogen that we know has five.
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We're going to add that to three times six for each of those oxygens.
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And we're going to add one valence electron because of that negative formal charge.
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So six times three we know is 18 plus six.
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It's going to make that a 24 electrons that we need to incorporate into this structure.
05:32
So we have our oxygens here.
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We have six right there, so we're going to take six away, making that 18.
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One, two, three, four, five, six, and twelve, thirteen, fourteen, fifteen, sixteen, seventeen, seventeen, eighteen.
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So we've got our 18 electrons.
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We go.
05:51
And we're going to look and we just want to make sure this follows the octet rule and formal charges we know has negative 1.
05:58
So we look at this.
05:59
Our oxygens right now as it stands are following the octet rule, but it is our nitrogen.
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It's got one, two, three, four, five, six.
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So it's not.
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It's only, it's got six.
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It needs eight.
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So we're going to do the good old make a double bond.
06:14
Okay.
06:14
When we do that, this is our new structure, nitrogen, oxygen, oxygen.
06:28
And let's see if this kind of helps out with our octet rule.
06:35
So, oxygens are still good.
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Nitrogen, 1, 2, 3, 4, 5, 6, 7, 8.
06:39
So now we're good, right? but now what we've got to do is look and say, okay, well, we know it needs to have a negative 1 formal charge on this buddy, and then we need to show resonance with these.
06:50
And so right now, as it stands, our oxygens, we know have six valence electrons for this one right here, we're looking at this oxygen, we are going to subtract the four balance electrons or free -floating electrons that are not in a bond, and we're going to subtract half of the bonds, of the electrons that are incorporated into a bond, making that a zero formal charge.
07:17
These ones will have each a negative one formal charge, and then our nitrogen right here, let's see what it's got.
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We know nitrogen starts with five.
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We're going to subtract one, two, three, four.
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Minus zero because it doesn't have any free floating minus four.
07:33
It's got a positive one formal charge there.
07:38
So could we do something here to help this alleviate, maybe get rid of some of these and only have one? and yes, yes we can.
07:50
So we're going to make that double bond there as well.
07:54
And so let's look at this.
07:55
Let's redraw this buddy boy again.
08:00
Nitrogen all right so anyways we've got this and what you're going to see is this is my personal opinion but we would see that this could be a resonant right here it is going to be sometimes in this form this one right here this could be another resonance that it could be in and then we could show resonance of it being maybe the double bond right here instead of right there or right there and the same thing right there so we could draw all these out i'm not going to spend that time, but you can see how that could kind of work there.
08:44
When we do this, this now has a negative zero formal or a zero formal charge.
08:48
This now has a zero former charge, but this one being the negative one.
08:52
And so we can see it now has a negative one formal charge.
08:57
And so this is another example of this that it could be in.
09:03
It'll be sometimes in this.
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It could be sometimes in this kind of format.
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Let's look at n204.
09:19
So we have n204.
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And i did a little cheat thing just to make sure that i did this correctly.
09:31
And then we have our two o's.
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Okay.
09:34
And so basically what is showing us is that the nitrogens will bond together, and then you'll basically have two oxygens coming off each end here as such.
09:43
But let's not jump the gun here, and let's count how many valence electrons.
09:47
Nitrogen we know has five each, so we have 10, plus our oxygen is six each, so six times four is 24.
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And so we have a total of 34 valence electrons that we need to incorporate.
09:58
We have one, two, three, four, five, six, seven, nine, ten, already taken care of.
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And so now we're down to 24.
10:05
One, two, three, four, five, six, nine, ten, eleven, twelve, thirteen, thirteen, fifteen, sixteen, sixteen, seventeen, eighteen, eighteen, nineteen, twenty, two, twenty -three, twenty -two, twenty -four, now we're down to zero.
10:19
And so now let's just make sure it follows the octet rule and also that we have everything good to go there.
10:28
So anyways, when we're looking at this, our oxygens are following the octet rule, but our nitrogens are not.
10:35
We have one, two, three, four, five, six.
10:39
One, two, three, four, five, six.
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And so these two both have a, oops, these guys are not following the octet rule.
10:52
Let's see what their charges would be here.
10:54
And so this would have a negative one, negative one, negative one, negative one, negative one, negative 1...