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Current time:0:00Total duration:9:28

Video transcript

so when we name organic molecules the core of what we think about is just how many carbons form the chain or form the ring that we're looking at so let's say I have something like this and hopefully you're reasonably familiar with what this represents and I'll review it a little bit so let's say I have something like this let's say that that is the molecular structure right there and so the first question you should be asking is how many carbons are there there and you and some of you might say wait how is that even a molecule and just as a review the end point of every line represents a carbon so that's a carbon that's a carbon that's a carbon that's a carbon that's a carbon that's a carbon and we have 1 2 3 4 5 6 carbons and we have no double bonds so if you have all of that information you're ready to name this molecule and before I actually name it let me just kind of give you all of the different prefixes so if you have one carbon if you have one carbon the prefix is meth the prefix is meth if you have two carbons the prefix is F and it's good to memorize at least you know up to about 10 and actually kind of repeats after that if you have three carbons the prefix is probe probe like propane and you've heard of ethane and methane so you'll see all of that soon for you're talking about butte five and after five it kind of becomes the the traditional prefixes that we associate with a lot of these numbers so at five it spent like pentagon six it's hex like hectic hexagon seven is kept eight is acht like octagon nine is NaN ten is Dec 10 is Dec and then after that it kind of starts to have a pattern here and you're not going to really deal with things much beyond the teens but I'll just write them down here just out of interest 11 is undec undec and for those of you who know French I'm not one of them but I know that that that one infringes une or or in Spanish you know so it's kind of one and ten eleven twelve is Doh deck Doh deck Doh Ordos if you're speaking Spanish for two deck for ten two and ten that's twelve thirteen you could imagine what it's going to be it is try deck try deck 14 is tetra deck tetra deck a tetrapod is something with four legs and then after that it becomes very systematic at 15 is Penta deck Penta deck notice pent pent five and ten sixteen is hexa deck 17 is hepta deck so it just goes on and on and on I don't think I have to go away x2 that CAPTA deck octobe deck is 18 19 is nan a deck and then 20 is actually I so but we won't even go into that this will probably serve our purposes I mean I could go up to you know 16 is hexa deck exit X so this is just how many carbons are in our longest chain what I drew here is just one chain so we can immediately let's try to name it what how many carbons do we have here well we have one two three four five six carbons so we'll be dealing with hex as a prefix and then to get I guess post fix on this prefix or the kind of the root you look to see if there are any double bonds here and there are no double bonds here and if we have no double bonds in this carbon chain we're dealing with an alkane this is called an alkane which is a general term for all of the chains of carbons that have no double bonds on or no triple bonds all single bonds so in this situation you take hex for six so this is hex and then because it's an alkane it gets the Ain from alkane so this is hex this is hexane let's do another one let's say I have this thing right here I'll draw let's make it even longer so let's say I have that thing right there so how many carbons do we have we have one two three four five six seven carbons they're all single bonds so an alkane so this will be we seven carbons it is HEPT heptane because we all have we have all single bonds now if things form a chain we or if things form a ring I should say we put the we've put the prefix cyclo in front of it so if I have let me show you what I'm talking about so if I just have five carbons 1 2 3 4 so 1 2 3 4 5 ok so that's five right there if 1 2 3 4 5 carbons in a chain if I just have 5 carbons in a chain like this this would be pentane pentane pentane but if I have 5 carbons and they form a ring so let me draw it so it's 1 2 3 4 5 carbons and it forms a ring let me make it a little bit let me make the drawing a little bit better so it's really I'm just drawing a Pentagon but notice this has 5 carbons on it I could draw the carbons here carbon carbon carbon carbon carbon and just as a review what you don't see is the hydrogen's they're bonded to each of these guys have two bonds so they must have two bonds with something else and those are going to be with hydrogen's and I'll draw it here just as a bit of a review but you notice very quickly the drawing gets extremely messy when you draw the two hydrogen's on each of these carbons so it's a bit little bit over maybe I shouldn't be doing that but there you go so it becomes very messy when you draw the hydrogen so it's better to just assume that they're there if we don't draw all four bonds on the carbon the other two bonds are going to be with hydrogen so here you might say okay this is an alkane because I don't have any double bonds here all of these are single bonds with the carbon I have five carbons so you might say this is pentane but you have to think about one more thing it's in a ring so we add the prefix cyclo to it so this is because it's a ring we write cyclo cyclo pentene cyclopentane so let me just break that apart this tells us that we're dealing with a ring you see that this is a ring right there this tells us this tells us that we're dealing with five five carbons and then this tells us right here the N part that tells us that they are all single bonds all carbon-carbon single bonds no double or triple bonds all single bonds so let's go the other way let's let's start with the word and let's see if we can figure out what the actual structure would look like so let's say I have let's say I have let me meet let's say I have cyclo cyclo nonane cyclone on name so what is this telling me this tells me I'm dealing with a ring that is a ring it's going to have a ring structure it's going to have nine carbons nine C's and then it's a alkane so they're all going to be single bonds it's all going to be all going to be single bonds single single bonds so if I want to draw it I want to draw nine carbons in a ring it's not a trivial thing to draw and try my best let's see that's one two one two three four five six seven eight that's about let's see em let me draw it let me try it a little a better shot at it so let's say I have one one two three four five six seven eight and then nine and then then you can connect the last year so let me make sure that this is and I obviously I could have drawn it better than that but hopefully you can see all the edges here so I have one two three four five six seven eight nine carbons so that is we have it's an it's in a cycle it's in a ring I have nine carbons they're all single bonded so this is cyclo nonane although there's probably better ways to draw that ring right there so if someone were to tell you if I someone were to tell you octane octane if someone were to tell you octane and that word might feel familiar to you from the gas station and they are literally talking about the molecule octane and you know what or at least you have a sense of what they're talking about the acht tells you that you have eight carbons there are there is no cyclo in front of it so it's not a cycle it's just going to be a chain and then the N part tells you that they're all single bonds so it's just going to be eight carbons in a chain one two three four five six seven eight it's just going to look like that one two three four five six seven eight in the next few videos we'll add more to these molecules and make the names even more complex