Physical Properties of Alkenes 8-1 When in the cis configuration, the methyl groups experience steric strain as they are in close proximity to each other. They avoid steric interactions when in the trans configuration as they are able to stay as far apart as possible. 8-2 8-3 Alkyl groups are able to stabilize their neighboring carbon atoms by donating electron density, which allows for the delocalization of electron density and an increase in stability. 8-4 a) Disubstituted b) Trisubstituted c) Monosubstituted d) Tetrasubstituted 8-5 Elements of Unsaturation and the Orbital Description of Alkenes 8-6 a) 4 b) 1 c) 2 d) 2 e) 5 f) 6 8-7 One sigma and one pi bond together make a double bond. Alkene Synthesis by Elimination of Alkyl Halides 8-8 8-9 8-10 8-11 (1 E )-1-chlorobut-1-ene Alkene Synthesis by Dehydration of Alcohols 8-12 8-13 8-14 8-15