For methyl-2-butene how do I know what the methyl group is coming off of?
A great question. And an equally great answer when you think about it. It MUST come off the 2 carbon BECAUSE if it came off the 1 carbon, it wouldn't be butene anymore would it? If the methyl group came off the 1 carbon, the chain would be 5 C atoms long and would be named 2-pentene. Right? So the first 2 in 2-methyl-2-butene isn't needed. Isn't chemistry fun?
Oh, I see it now. Thanks so much :)
To determine the position of the methyl group in methyl-2-butene, you need to consider the numbering system used for alkene compounds.
Follow these steps to determine the position of the methyl group:
1. Identify the longest continuous carbon chain in the molecule. In this case, we have four carbons in the longest chain, so it is a butene.
2. Number the carbons in the chain starting from the end closest to the double bond, to create the lowest possible numbering. In terms of the molecule methyl-2-butene, the carbon closest to the double bond will be designated as number 1.
3. Once the numbering of the chain is established, locate the position of the methyl group using the assigned numbers. In this case, if the methyl group is attached to the second carbon of the butene chain, it will be called "2-methyl-2-butene."
Remember, the position of the substituent groups is indicated by the lowest possible numbers to provide systematic naming.