Why is this NOT an isomer of hexane. Is the name of the compound correct? (by me, 2-ethylbutane) It says that hexane only has four isomer, and the one I mentioned is not anywhere at all. What is wrong with this compound?
It's the same look at the LONGEST carbon chain in your original molecule. The carbon that's furthest on the left is your methyl group and the other five form the pentane backbone. xx
How come the longest chain is 5 carbon long? I see only four.
The longest carbon chain formed is 5 carbons long. Go across 3 from the right and down 2, that's 5 carbons. The one on the left is the methyl group, and it's attached to the third carbon so it's 3-methylpentane.