4.1 Stereoisomerism Flashcards
(13 cards)
What are structural isomers?
Molecules which have the same molecular formula but different structural formulae
What are stereoisomers?
Molecules that have the same molecular and structural formula but a different spatial arrangement atoms
Examples of stereoisomerism
E-Z isomers
Optical isomers
What are E-Z isomers?
Two molecules that have the same molecular and structural formula but their atoms have different spatial arrangement
What are optical isomers?
Two molecules that have the same 4 groups arranged around a central carbon atom, the groups are arranged different in space
What is a chiral centre
A central atom (carbon) that has 4 different groups bonded to it
What are enantiomers?
Two optical isomers that are non-superimposable mirror-image isomers
What is optical activity?
A solution that can rotate plane polarised light
What is a racemic mixture?
An equimolar mixture of both optical isomers
How to identify the chiral centre
Placing a star next to it
What does it mean that two optical isomers are non-superimposable
They are mirror images of eachother
What structure should optical isomers be drawn in?
Tetrahedral 3D structure
Note a physical property which two enantiomers have and which can be used to distinguish between them.
Enantiomers rotate the plane of vibration of plane polarised light in opposite directions
1 will rotate it clockwise
The other will rotate it anti-clockwise but to the same angle
