Show all possible resonance structures for each of the...

Key Concepts

Formal Charge Calculation

Formal charge calculations are used to assess the distribution of electrons in a Lewis structure. By assigning formal charges to atoms based on electron counting rules, chemists determine which resonance structures are most significant and contribute more to the overall resonance hybrid.

Resonance Structures

Resonance structures are alternative ways of drawing the electron distribution in a molecule or ion using Lewis structures. They illustrate how electrons can be delocalized over two or more atoms, providing a better representation of the real electron density distribution which cannot be captured by a single Lewis structure.

Lewis Structures

Lewis structures are diagrams that show the bonding relationships and lone pairs of electrons within a molecule. They are foundational in understanding chemical bonding and are used as the starting point for determining possible resonance forms.

Electron Delocalization

Electron delocalization is the concept that electrons are not confined to a single bond or location in a molecule but can spread over several atoms. This delocalization, depicted by multiple resonance structures, is key to understanding the stability and reactivity of many molecules and ions.

Transcript

00:01 So for this question, we're basically given these three molecules and we're asked to find all the resonance structures, all the possible resonance structures for each of the molecules are ions.

00:11 So the first molecule we're given is nitrate ion, no3 minus.

00:19 So let's start out by just looking at no3 minus.

00:23 So let's draw basically the first lewis structure that comes to mind.

00:29 So we draw nitrogen in the center.

00:34 Then we'll have some oxygens, minimally bonded by one.

00:39 And then we will realize that...

00:43 Let's actually go ahead and calculate the electrons required and the valence electrons as well real quick before we go any further.

00:50 So electrons required, each of these requires 8 by the octet rule.

00:55 So it's 8 times 4, that's 32 electrons required.

00:58 Valence electrons, for nitrogen, we have five valence electrons.

01:09 And each of the auction has six, so that's going to be six times three.

01:15 So from there, we can sum these up.

01:19 So we have 6, 12, 18, 18 plus 5 gives us 23.

01:25 And don't forget, we actually have a minus here, so we need to add one to this number of valence electrons.

01:30 So that brings us up to 24.

01:33 And then the difference between that is going to be 8.

01:35 8 divided by 2 gives us 4.

01:36 Four shared pairs.

01:38 So right now we only have three shared pairs.

01:40 So that's probably where our resonance is going to come into place.

01:43 So let's just go ahead and start by adding that extra shared pair to this oxygen right here.

01:49 So that means this oxygen will have a, we'll have two loan pairs to satisfy its octet rule.

01:56 This auction will have three lone pairs to satisfy its octet rule and same for this top oxygen.

02:03 So this is going to be one of our resident structures.

02:09 Let me move it over here real quick.

02:11 So right there and right there.

02:14 And we should notice that this is a negative.

02:17 This has a minus charge.

02:19 So that's one of our lewis structure.

02:23 So let's go ahead and draw our second lewis structure.

02:25 And for that, all we're simply going to do is take the same structure and move the second shared pair to another oxygen.

02:33 So then we'll fill in our octet rule, just the same as before.

02:37 And that's boom that's our going to be our second structure then we'll finally go to our third structure which is going to be oh and oh oh and we'll have two shared pairs between the oxygen at the top and the nitrogen over here and then we'll fill in our share our tett rule loan pairs and then finally that's going to be our very last louis structure so that is going to be the resident structures for our first molecule, the nitrate ion.

03:12 So then let's go on to our second molecule, which is nitric acid.

03:19 And nitric acid has formula hno3.

03:27 From here, let's once again, let's once again go ahead and look at our resin structures.

03:40 So i guess once again we can start with our valance electrons and electrons required, right? that's the wrong order.

03:48 But essentially, we'll start by doing out the math first.

03:53 So the electrons required for nitrogen and oxygen are both going to be eight.

03:56 So we have four of those.

03:57 So that's going to give us 32 electrons required.

04:02 The valence electrons, oh, sorry, we still need to add the hydrogen in here.

04:07 So we need to add two more...

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