• Question: what do the suffix Cis/Trans mean when talking about alkenes

    Asked by Plasma_based_lifeform to Anne, Arthur, Rose, Ruhina, Thomas on 18 Jun 2015.
    • Photo: Rose Simnett

      Rose Simnett answered on 18 Jun 2015:

      Cis and trans refers to where the functional groups are arranged across the carbon-carbon double bond. A cis bond is where the two groups are on the same side of the double bond. It is called a cis bond because in Latin cis means on the same side.
      A trans bond has the groups on opposite sides of the double bond. Trans means on the other side in Latin.

    • Photo: Ruhina Miller

      Ruhina Miller answered on 18 Jun 2015:

      For an alkene: R-C=C-R, where R are the groups or atoms attached to the alkene, cis is when both atoms/groups are on the same side of the molecule, whereas trans is when one atom/group is on the opposite side.

      Try drawing R-C=C-R out on your paper but have the “R” groups pointing diagonally.

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