Let's go ahead and add a few more functional groups. So now we're going to talk about alkenes, alkynes, and alcohols. First, let's start off with the pi bonds, with the double bonds and the triple bonds. Alkenes and alkynes are going to be named by adding a modifier. This is going to be the very first time that we're using a modifier in an IUPAC name, so I'm going to teach you how to do this. What that means is that instead of using the ending -ane, like we always use that stands for alkane, we're going to modify it to either be ene if it's an alkene or yne if it's an alkyne. That's why we call it a modifier; it modifies the root name. Now, all of a sudden, a hexane becomes a hexene if it has a double bond or a hexyne if it has a triple bond in it. Does that make sense? Cool.
So then let's talk about some important rules here. Alkenes and alkynes actually receive priority in numbering over alkanes. This is going to be the very first time that now, when it comes to numbering the chain, we are going to give priority to this group. What that means is that I don't care about the closest substituent. All I care about now is how do I give my double bond or my triple bond the lowest number possible. Isn't that interesting? So now, I'm just thinking about how can I make that number as low as possible. Then finally, this can get tricky because these double bonds go over 2 carbons. So sometimes it can be tricky. What's the location? Is it in the 1st carbon or the second carbon? The location is always assigned to the 1st double bonded carbon or triple bonded carbon. So what I want to do here is I want to go ahead and name this compound. I want you all to go ahead and try it first with the rules and then I'll go ahead and I'll give you the name.
