Draw a Lewis Structure for each species.
e. CH₃

Question

Draw a Lewis Structure for each species.

e. CH₃CHO

f. CH₃S(O)CH₃

g. H₂SO₄

h. CH₃NCO

Accepted Answer

Okay, hi everyone, let's solve this problem. It reads right, the appropriate lewiS structures for each of the following species. H ch oh ch three, C O ch three, H two, S 03 and H N C. O. Well, if you recall lewiS structures include all the valence electrons for all of the atoms in a compound. So first we need to determine the total number of valence electrons that we're going to use in our structure. And how do we do that? Yeah, we just add up the basically group number of each atom in the periodic table. So I'll write periodic table there. Then we're going to draw like a rough draft structure of just sigma bonds or single bond. So just showing how those atoms are connected. And then once we see how many electrons we used versus how many more we need or how many more we have left over. We will complete the octet by adding those final electrons to the structure as lone pairs. And then we might have to form some double bonds to satisfy the octet for the rest of the structure. So let's apply these steps to our structures. So we have H C H O. If you add up their group numbers you'll find they have 12 valence electrons. So let's draw our sigma bond structure H C H O. And this uses six electrons which means I have six more left over and that will be six alone or not six lone pairs, Three lone pairs. Right? So We can add three lone pairs to the structure. So I will just add them to the oxygen Because that satisfies the oxygen's octet. Right. 2468. But like I said in step three the carbon is not ready to It's not satisfied. Right? Its octet is not full. It only has six octet electrons. So we're going to take two of those oxygen electrons and donate them to that charge center. So we have double bond O. C. And now are all of our atoms are happy. So this is our lewiS structure for that compound. All right, let's move on. We have CH three C O CH three. This is 24 valence electrons. And that will look something like this. We have our CH three which is a methyl group bonded to a carbon that is bonded to an oxygen. And then we have another CH three group. Methyl group. Cool. And that uses 18 valence electrons. Which means we have how many left over six. And again, that is three lone pairs. So let's add three lone pairs. This is kind of similar to the last one. Right? I'm just going to pop them on that oxygen. Okay. And now again I see oxygen is satisfied but carbon is not so we can have that oxygen share the electrons with that carbon via a double bond. So let's redraw what that will look like C double bond O. Now the O. Has only two lone pairs. And our metal group. All right. That's the 2nd 1. How's it going? You feeling good about these? I think you got it. All right, let's do the next one. So we have H two S. 03. So a little bit different. We don't have a carbon chain or carbon central atom but sulfur will be our central atom because we'll choose the atom with the highest bonding preference that will go in the middle. So the atom that can create the most bonds. So we're gonna add the oxygen's first and then we can add those hydrogen to the outside on those two, oxygen's Alright. 2468, 10 valence electrons. Oh wait, I forgot to finish step number one. So that will be 26 valence electrons total. We just use 10. So that means we have 16 left over that we can use which would be eight lone pairs. Alright, so let's add these lone pairs. I'm going to add them to the oxygen because I see their octet is not complete. So that's 2468. And I'm going to add them to this oxygen in the center too. 2468, 10, 12, 14. And I see sulfur is also missing some electrons. So I'll add one there. Cool. So now which Adams still needs some work done. Well these oxygen atoms are happy. But I see that sulfur. Although the octet is satisfied for these two atoms. Right? They have formal charges. So there's 1234567 electrons touching that oxygen. So that has a formal charge of negative one. And the sulfur has 12345 electrons touching it. So it has a plus one charge because it's in group six so we can neutralize, so to speak, the formal charge on those atoms by donating one of these lone pairs from that oxygen down to the sulfur bond. So then we will have this and then that sulfur still has a lone pair. Okay, so now all of our atoms have a formal charge of zero. All their octet is satisfied. So we're done there. Sweet. Alright, last one. Hang in there. So we have H N. C. O. Okay, and this totals to 16 valence electrons. So we'll draw H N C. O with our sigma bonds and that is six valence electrons. So I have 10 more Which will be five loan pairs. So five more lone pairs. Let's start with oxygen. Because I see it has barely any electrons. So eight hmm 123412345. I'll just add them there. Mhm. Actually I'm gonna add one to the nitrogen. Yeah, because nitrogen is also missing electrons. So 12345 lone pairs. There we go. Sorry guys. So, Alright, let's see where we need to shift any electrons. So we see that carbons octane is not full. Right? It only has 246 octet electrons. So let's take one lone pair from that oxygen. Since it has a negative formal charge, it can share those electrons And then carbon will be satisfied. But then nitrogen is not satisfied, right? It only has 2460ctet electrons. So then this lump air can go down onto that nitrogen and we'll have a church bonded to N double bonded to carbon double bonded to oxygen. Okay, so those are our leWIS structures for these compounds. I hope this video is hopeful and thanks for watching.

Draw a Lewis Structure for each species.
e. CH₃CHO
f. CH₃S(O)CH₃
g. H₂SO₄
h. CH₃NCO

Key Concepts

Lewis Structures

Valence Electrons

Formal Charge

Watch next