Names and Physical Properties of Cycloalkanes

Cycloalkanes have their own names under lUPAC rules, and their properties are generally different from those of their noncyclic (also called acyclic) analogs with the same number of carbons. We will see that they also exhibit a kind of isomerism unique to cyclic molecules. 

Make molecular models of cyclopropane through cyclododecane. Compare the relative conformational flexibility of each ring with that of others within the series and with that of the corresponding straight-chain alkanes. 

CH2CH2CH3 1 -Chloro-2-inethyl-4-propylcyclopeiitane (Alphabetical not 2-chloro-l-methyl-4-propylcyclopentane) 

Inspection of molecular models of disubstituted cycloalkanes in which the two substituents are located on different carbons shows that two isomers are possible in each case. In one isomer, the two substituents are positioned on the same face, or side, of the ring in the other isomer, they are on opposite faces. Substiments on the same face are called cis (cis, Latin, on the same side) those on opposite faces, trans (trans, Latin, across). 

We can use hashed-wedged line structures to depict the three-dimensional arrangement of substituted cycloalkanes. The positions of any remaining hydrogens are not always shown. 

---