Alkenes

Question 1

Pi bond definition

Answer 1

Sideways overlap of p-orbitals

Question 2

Stereoisomers definition

Answer 2

Compounds with the same structural formula, but a different arrangement of atoms in space

Question 3

Criteria for E/Z stereoisomerism

Answer 3

• The molecules must contain a carbon-to-carbon double bond which restricts rotation
• Both carbons in the double bond must have 2 different groups attached to them

Question 4

Cahn - Ingold - Prelog rules

Answer 4

• Atoms in C=C are given a priority number based on their atomic number
• Highest priority groups on same side —> Z stereoisomer
• Highest priority groups on opposite sides —> E stereoisomer

Question 5

Cis/ Trans

Answer 5

• One group on each carbon in the double bond is the same
• Same group, Same side —> Cis
• Same group, Opposite side —> Trans

Question 6

What reactions do alkenes participate in ?

Answer 6

• Hydrogenation - Addition of H2
• Hydration - Addition of water
• Halogenation - Addition of a halogen
• Halogenation with hydrogen halide
• Electrophillic addition - Formation of carbocation first then addition of a halide