Predict the hybridization and geometry of the carbon and nitro...

Question

Predict the hybridization and geometry of the carbon and nitrogen atoms in the following molecules and ions. (Hint: Resonance.)

a.

b.

c.

Accepted Answer

Hey everyone. Let's solve this problem. It says keeping the resonance in mind suggest the hybridization in geometry of the central atoms only carbon and nitrogen in the given species. All right, well, let's number our carbons 123. And let's look at the hybridization of each one. Now it mentions keeping the resonance in mind that's important. Especially with lone pairs. Okay, so keeping in mind lone pairs for residents. So we might have to draw out. I think it will benefit us to draw out the resonance structures for each compound. Okay, So let's draw out compound a. We have CH three C double bond, O N H two and we want to make sure we add the lone pairs. So there should be a lone pair on that nitrogen right to complete its octet. So are there possible resonance structures for this compound? Yes, because I have a lone pair and it's next to that double bond. So those electrons can move down here and the electron from the double bond will go up onto that oxygen which will give me a resonance structure that looks like this. So, I'm gonna draw out these hydrogen in our initial structure. It looks like our compound or the nitrogen rather has four charge centers. Let me draw out the hydrogen Right? 1, 2, 3, 4 which would be sp three hybridized. Right? But if you notice the resonance structure, those electrons participate in resonance Which gives us three charge centers. I forgot to change this double blond so that lone pair actually cannot participate in hybridization because the lone pair is conjugated with the pi bond in the carbonell. So that nitrogen or our atom number three is going to be S. P. Two hybridized. Okay. And why did I skip number one and two? I don't know. So let's go back and do those. So CH three bonded to another carbon. That's going to be sp three hybridized. Right? Four charge centers in that central carbon is still going to have three charge centers no matter which resident structure you look at. So that is S. P. Two. Okay, so again, just be careful of the loan pairs that could participate in resonance. I was just so excited to tell you about that, that I skipped to number three. So, in our second structure, we have 1, 2345 atoms we're looking at. Let's draw our structures. We have CH three Bond into carbon with a CH2 on the other side. And that has a positive charge. And that central carbon is double bonded to carbon with a hydrogen and then we have NH2. All right, so, let's go through our list. So, carbon number one has four charge centers. So that is S. P three. Carbon number two has 123 charge centers. So that is S. P two. Carbon No three. No, I want these different colors. Has 1, 2, 3 charge centers. So that is s. p two. Carbon number four has 123 charge center. So that is S. P. Two. And our nitrogen has a lone pair, right? So it looks like four charge centers. But again we see that lone pair is pretty close to a double bond. So let's see what the resonance structure looks like. Oops. So that lone pair is going to move down here and the electrons in this double bond are going to travel towards that positive carbon down here. Right. We want to fix that carbon with a positive charge. So these bonds are going to change. We have the nitrogen now has a double bond to that carbon and there's also a double bond here between those two carbons which gives us a positive charge on these two atoms. So similar to the first one, you'll see that although nitrogen had four charge centers in the first resonance structure, that lone pair is again participating in resonance. So it is not participating in high hybridization. So we can only count three charge centers which will make it S. P. Two. Okay, cool. Last one, we have Only two atoms. one. Well, two atoms were looking at. And let's draw our structure, N. H two, Bonnie to see H two. Okay. And we know nitrogen has a lone pair red flag. So we see nitrogen has 1234 charge centers. But again, lone pair next to that positive charge is a little sketch. So that lone pair can move down and create a resonance structure that looks like this with a double bond between the nitrogen and carbon. And now we have a positive charge on that nitrogen. So again, we see that there's only three charge centers that are actually able to to participate in the hybridization so that nitrogen is going to be S. P. Two and that carbon has three charge centers in both structures. So that is S. P. Two as well. And the problem also mentioned the geometry. Let's not forget that. So instead of writing it 20 times, I'm just going to write that S. P. Two atoms have a tribunal plane, are geometry, and sp three atoms have a tetra he drel, right, Because there's no loan pairs involved in the hybridization. So those don't count towards the geometry, Right? That's it for this problem. And I hope this video is helpful. Thanks for watching.

Predict the hybridization and geometry of the carbon and nitrogen atoms in the following molecules and ions. (Hint: Resonance.)
a.
b.
c.

Key Concepts

Hybridization

Molecular Geometry

Resonance

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