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<\/a><\/p>\nFurther into your organic chemistry odyssey, you are going to worry about how you might synthesize this molecule.\u00a0 Right now, you are merely concerned with what to name it.\u00a0 Is this a cis or trans alkene?\u00a0 Unfortunately, cis and trans do not apply to more complex alkenes, so we need a new system of nomenclature.\u00a0 Enter the Cahn\/Ingold\/Prelog\u00a0<\/strong>system for naming double bonds.<\/p>\n The system itself is simple: assign the atom connected to the olefin a priority based on its atomic number then determine whether the two highest priority groups are on the same side of the double bond, or on opposite sides.\u00a0 For example:<\/p>\n <\/p>\n In the above example, we compare Cl to F and quickly determine the Cl is of greater priority based on its atomic number.\u00a0 When the same comparison is made for H and CH3<\/sub>, we determine that C is the higher priority.\u00a0 Thus, the alkene above is an \u201cE\u201d alkene.<\/p>\n Further, there is a nice mnemonic used to remember which letter goes with which alkene:<\/p>\n –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u201cZ\u201d alkenes are on the \u201cZAME side\u201d<\/p>\n –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u201cE\u201d alkenes are far \u201cE-WAY\u201d from each other.<\/p>\n <\/p>\n <\/p>\n While figuring out which type of alkene is present is easy when there are four different atoms connected to the alkene, we have to ask what would happen if there was a tie because there were two of the same atom on the alkene.<\/p>\n In the above alkene, we are posed with the problem of four carbon atoms bound to the double bond.\u00a0 Here, we can use the AceOrganicChem.com method for determining priority.\u00a0 For each substituent on the alkene, write out the atom attached directly to the alkene and each of the three atoms attached to it, in order of atomic number.\u00a0 For example, -CH3<\/sub> would be C (H, H, H), and -CH2<\/sub>CH3<\/sub> would be C (C, H, H).\u00a0 If we were to say what we were writing, an ethyl group of C (C, H, H) would translate to \u201ca carbon with one carbon and two hydrogens attached to it\u201d.\u00a0 Since they are already in the parentheses in order of atomic number, ties are easy to judge.\u00a0 If the first atoms in the parentheses are the same, just go to the second atom to break the tie.\u00a0 Thus, an isopropyl group with C (C, C, H) outranks an ethyl group with C (C, H, H)<\/p>\n Now, our molecule looks like this:<\/p>\n <\/p>\n It can now easily be seen after the naming alkenes,\u00a0this is an \u201cE\u201d alkene.\u00a0 This method can also be applied to other functionalities common found attached to olefins:<\/p>\n <\/p>\n <\/p>\n The trick to looking at these groups is to recognize that a double bond on the substituent is equal to two of that type of atom. For example, a cyano group would be equal to C (N, N, N).\u00a0 Another example of this would be as follows:<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n