Nomenclature
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how would you write the number of carbon atoms for a molecule
• by using a letter code - like meth = one carbon atoms or prop = three
what is the mnemonic for the first five number of carbon atoms
• Monkeys Eat Peeled Bananas (Partially) • M = meth = one carbon atom • E = eth = two carbon atoms • P = prop = three carbon atoms • B = but = four carbon atoms • P = pent = five carbon atoms
why are suffixes and prefixes used when naming molecules
• to indicate the presence of atoms other than carbon and hydrogen
how would a suffix or prefix be written with 2 examples
• by adding other letters before or after the code for the number of carbon atoms • like bromo = an atom of bromine, making bromoethane • or ol = a hydoxyl group (OH) at the end of alcohols
why would you need to multiply prefixes and are the common ones
• to show the presence of two or more identical groups - usually with di or tri = two or three
what are locants
where atoms and groups can have different positions in a molecule
what are used to show the positions of locants in the name of a molecule
numbers and hyphens
what do the numbers used to show locants specifically indicate
the carbon atom in the longest chain that the group is attached to
what would a locant of 2- be telling us
• that the group of atoms are attached to the second carbon atom • in the longest chain of carbon atoms
what are the codes and prefixes for the number of carbon atoms up to 5
• meth = methyl • eth = ethyl • prop = propyl • but = butyl • pent = pentyl
what is the name of CH3-CH2-CH3
propane
what is the name of CH3-CH-CH3 | CH3
methylpropane
why doesnt that methylpropane have a 2- at the beginning of it to show the locant
• if the methyl group was attached to the first or third carbon atom • that would simply make a chain 4 carbon atoms long • making it butane • therefore the locant isnt needed at that is the only position the methyl could be in for the code to still be prop(ane)
what is the name of CH3-CH2-CH-CH2-CH3 | CH3 and why
3-methlypentane • the longest chain consists of 5 carbon atoms • and the methyl is attached to the third carbon atom • this time the locant can be shown because the code wouldnt change if it was bonded to the 2nd or 4th carbon atom
what is the name of CH3-CH2-CH2-CH-CH3 | CH3 and why
2-methylpentane • it is not 4-methyl as the lowest locant should be used • considering 4 and 2 would both indicate exactly the same molecule • just flipped over
what is the name of: CH3 | CH3-CH-CH-CH3 | CH3 and why
2,3-dimethylbutane • there are two locants showing where two of the methyl molecules are • the numbers should be in chronological order from the smallest if it is the same prefix • because there are two you multiply the prefix to dimethyl • and the longest chain that can be made consists of 4 carbon atoms so it is butane
what is the name of: CH2-CH3 | CH3-CH2-CH-CH-CH3 | CH3 and why
3-ehtyl-2methylpentane • the prefixes must be in alphabetical order if they are different • it is not 4methyl as that isnt the smallest number • and 3 + 4 is higher than the number of carbon atoms making the longest chain(5) which would be 3 + 2
what is the name of CH3-CH2-OH
ethanol
what is the name of CH3-CH2-CH2-OH
propan-1-ol
what is the name of CH3-CH-CH-CH3 | | OH CH3
3-methylbutan-2-ol • it is not 2-methylbutan-3-ol because the lowest locant should be used for the suffix over the prefix • as the suffix indicates the functional group
what is the name of: CH3 | CH3-C-CH2-CH2-OH | CH3 and why
3,3-dimethylbutan-1-ol • the use of prefixes, suffixes and a comma is kinda long • the suffix comes first so its 1 going from right to left • the two methyl molecules are bonded to the 3rd carbon atom in this direction • so the multiplied prefix is dimethyl and you have one on the 3rd twice • giving 3,3
what would dimethylpropane look like
CH3 | CH3-C-CH3 | CH3
what would 3-methylbutan-1-ol look like
CH3-CH-CH2-CH2-OH | | CH3 (OH) or this