How to Read Bond-Line Drawings

Bond-line drawings show the carbon skeleton (the connections of all the carbon atoms that build up the backbone, or skeleton, of the molecule) with any functional groups that are attached, such as - OH or -Br. Lines are drawn in a zigzag format, where each comer or endpoint represents a carbon atom. For example, the following compound has 7 carbon atoms  

It is a common mistake to forget that the ends of lines represent carbon atoms as well. For example, the following molecnle has six carbon atoms (make sure you can count them)  

Double bonds are shown with two lines, and triple bonds are shown with three lines  

When drawing triple bonds, be sure to draw them in a straight line rather than zigzag, because triple bonds are linear (there wiU be more about this in the chapter on geometry). This can be quite confusing at first, because it can get hard to see just how many carbon atoms are in a triple bond, so let s make it clear  

It is common to see a small gap on either side of a triple bond, like this  

Don t let triple bonds confuse you. The two carbon atoms of the triple bond and the two carbons connected to them are drawn in a straight line. All other bonds are drawn as a zigzag  

EXERCISE 1.1 Count the number of carbon atoms in each of the following drawings  

Answer The first compound has six carbon atoms, and the second compound has five carbon atoms  

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