optical isomerism Flashcards
what 2 types of isomerism are studied during a level chem
structural and stereoisomerism
structural isomers
compounds with the same molecular formula but different structural formula
stereoisomers
same structural formula but different arrangement of atoms in space
two types of stereoisomerism
- e/z
- optical
what does e/z isomerism occur as a result of
retricted rotation about the planar c-c double bond
do all alkenes have e/z isomerism
no
what must an alkene have to exhibit e/z isomerism
each carbon of the c=c bond must be bonded to different groups
how to determine whether an alkene is the e or z isomer
- identify highest priority group on each c atom of c=c bond
- if both highest priority groups are on the same side of c=c- z isomer
- if both highest priority groups are on opposite sides of the c=c bond- e isomer
how do the cip rules allow the highest priority to be determined easily
- atom with highest atomic number has highest priority
- if 2 atoms have same atomic number, the next atom along the chain should be compared
optical isomers
non superimposable mirror images
what must a compound contain to exhibit optical isomerism
carbon has to be bonded to 4 different groups
what is the asymmetric c atom in an optical isomer called
chiral carbon
what are optical isomers called
enantiomers
what do optical isomers differ in their effect on
plane polarised light
how do enantiomers rotate plane polarised light
by an equal amount but in opposite directions
