Compare the O—O bond length in O2 versus H2O2. Which
bond is sho...

Question

Compare the O—O bond length in O2 versus H2O2. Which 
bond is shorter? Why?

Accepted Answer

Hello. Everyone in this video we're taking a look at different lewis structures and risk ranking the carbon auction bonding of three different molecules from longest to shortest. So let's go ahead and also recognize before we draw the lower structure, we need to know the number of valence electrons here. We're only dealing with two different atoms carbon and oxygen. So carbon is in group four a. So that gives us four bands electrons And oxygen is a group 68. So there's going to be six valence electrons. Alright, so first molecule that we're dealing with is going to be our C. O. So we have four advanced electrons from that one carbon and then we have six valence electrons from our oxygen. Four plus six is equal to 10. So in this molecule we have 10 fans electrons. So drawing out the lewis structure, we have our cartman and auction adam connected through a triple bond and to fulfill its octet will give one lone pair to each atom. Next we have R. C. 02. So really well known carbon dioxide, so C. 02. Again we have that one carbon atom that's four fans electrons And then we have two oxygen atoms each giving us six bands electrons. They're just doing the math here. Now We have the four plus and two sexes. That's going to equal to 16 valence electrons. Now we have our carbon is our central atom Double bonded to two oxygen's and now the carbon has fulfilled its octet But the oxygen still needs four valence electrons, how can do that? It's just by giving it too long pairs per adam. Alright now, lastly we're moving on to our an eye on here because of the two minus charge. So we have C 032 minus. Let's just temporarily ignore that two minus charge. So our carbon provides us for veils electrons And this time we have three Auction items each giving us six electrons And so doing the math. Heard we are given a sum of fans electrons. Now we can deal with the two minus charge having to minus charge. Just means that we have two extra electrons adding to here. 32 plus two is 34 electrons join the lower structure for that will have carbon again being the central atom connected to three oxygen atoms. So oxygen usually likes to have two bonds. However, that would break octave rules if we have double bonds for each oxygen atom so we'll only give to one of them. And of course we need to fulfill its octet rule still. So we'll just go ahead and fill in with long pairs in this ocean Adam will have a negative one charge as well as this one right here. And if you add the formal charges of negative one and negative one, you'll get negative two just like the iron suggests. And so let's see here to keep in mind when ranking the bond lengths, it's that our single bond is going to be the longest but the weakest then we have our double bond which is just in the middle and then we have our triple bond which is going to be the shortest and the strongest. So think of it as a rubber band, the longer you stretch it, it's going to be longer. Yes but it's definitely going to get a lot weaker. Alright so we can see your hair that we have a clear triple bond and a clear double bond. But what about this one right here? Well we can go ahead and actually draw different resonance structures for this. You can see here we have this pipe on this can go ahead and break and create a long parent. And one of these lone pairs can go ahead and form a double bond so that we can have several resident structures. And because of that we know that resonance structures are kind of like a hybrid of all. To create an accurate representation of the molecule. In that case is that of a double bond. Or a single bond will kind of average it out. And then we have average that's going to actually be 1.5. So we have a triple bond here, we have a double bond and have that 1.5. So because 1.5 is close enough to single, they will name this being the longest but the weakest. And then we have this triple bond here being the shortest and the strongest. So if we follow this little guide map here, then our answer should be again from longest to shortest. We will have a c. two minus, Then CO two unless they are C. O. And this is going to be our final answer for this problem. Thank you all so much for watching.

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