1. Chemsheets AS006 (Electron arrangement)
21/09/2018
GEOMETRIC ISOMERISM
© AS Jul-12

3. X GEOMETRIC ISOMERISM CANNOT ROTATE AROUND C=C
© AS Jul-12

4. GEOMETRIC ISOMERISM (E) but-2-ene (Z) but-2-ene E entgegen (opposite)
Z zusammen (together)
© AS Jul-12

5. GEOMETRIC ISOMERISM PRIORITY: H < CH3 < CH2CH3
Look at atomic numbers of atoms attached to C=C (or subsequent atoms if the same).
Highest values opposite = E
Highest values together = Z 6
6, 6 6 6 6
E 2-bromo-3-fluorobut-2-ene
E 3-methylpent-2-ene
© AS Jul-12

6. BOTH C ATOMS OF C=C MUST HAVE
GEOMETRIC ISOMERISM
trans but-2-ene
(E) but-2-ene
cis but-2-ene
(Z) but-2-ene
BOTH C ATOMS OF C=C MUST HAVE
TWO DIFFERENT GROUPS
© AS Jul-12

7. TASK NO YES E Z methylpropene 1-chloropropene
© AS Jul-12

8. TASK NO NO 2-methylpent-2-ene 2-ethylpent-1-ene
© AS Jul-12

9. TASK YES E Z NO 3-methylpent-2-ene but-1-ene
© AS Jul-12

10. TASK YES Z E YES E Z 3,4-dimethylhex-3-ene 2-bromo-3-chlorobut-2-ene
© AS Jul-12