In chemistry, every single molecule needs a unique name. We can’t have two molecules with the same name or that would get super confusing! For this, we use IUPAC nomenclature.
Concept #1: The different parts of an IUPAC name
Basically there are 4 different parts to naming most molecules:
Concept #2: Learning Alkane Prefixes up to 12 Carbons in Length
Memorizing sucks, I get it. But unfortunately this is something you’re just gonna have to remember. Not all professors will make you memorize all 12 so check with your professor to figure out how many you need to know!
Concept #3: Naming the root chain
Remember, if there is a TIE between two chains of equal length, go with the chain that gives the MOST substituents!
Now we know the length of the root chain, but nothing else! We need to determine which carbon gets the “1” location.
Concept #4: How to determine the direction of the root chain
The key here is to get the lowest numbers possible for ALL of your locations (at least for now). Now give it a shot by yourself with these examples!
Example #1: Name the longest carbon chain and determine the direction of the root chain
Example #2: Name the longest carbon chain and determine the direction of the root chain
If you got this one wrong, don’t worry too much. You’ve got plenty more chances to nail this.
So we know the length and direction of the root chain, which is great. But if there are ANY branches on this chain, we need to name those too.
P.S. The term “substituent” is just a nerdy word for a “branch”.
Concept #5: How to identify and locate branches (substituents)
NOTE: Alkane substituents require a “-yl” suffix to indicate that they are a branch! (i.e. ethane becomes ethyl).
Example #3: Name the root chain, determine the direction of the root chain and then identify & locate all substituents
Sick job! We’re getting closer to fully naming these guys.
Now we have all the pieces we need to name most alkanes, but we need to work on our formatting! Chemists are surprisingly analytical making sure all your commas and numbers are in the right place.
Concept #6: Proper name ordering and punctuation
Example #4: Provide the IUPAC name for the following alkane
Does this make sense? You just learned how to name simple alkanes. Give yourself a pat on the back!