You need to figure out if the two “most important” groups are on the “same side” of the double bonds (CIS) or on “opposite sides” of the double bonds (TRANS). Then, the word ‘cis’ or ‘trans’ just goes in front of the regular molecule name.
i.e. cis-pent-2-ene, trans-but-2-ene.
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Post time: Aug-09-2017