4.4 Isomerism and Nomenclature Flashcards
What are Positional Isomers?
Molecules with the same molecular formula but have the functional group on a different position in the molecule.
What are Functional Group Isomers?
Molecules with the same molecular formula, but different functional groups.
Name the three different types of Structural Isomers:
- Chain Isomers
- Positional Isomers
- Functional Group Isomers
What are Stereoisomers?
Molecules that have the same structural formula but a different arrangement of atoms in space.
Name the two different types of Stereoisomers:
- E/Z Isomers
- Optical Isomers
What is the cause of E/Z isomerism?
Restricted rotation around the C=C Double bond
What name is given to a carbon atom that is bonded to four different atoms, or groups?
Chiral or asymmetric carbon
What is a Chiral/Asymmetric Carbon?
A carbon atom that is bonded to four different atoms, or groups.
When do Optical Isomers occur?
When a molecule contains a Chiral/Asymmetric carbon atom
Define Optical Isomers:
Molecules that contain a chiral/asymmetric carbon and exist as non super-imposable mirror images.
What is the name for two optical isomers?
A pair of enantiomers
How do you distinguish between two enantiomers?
They have opposite rotation of plane polarised light
What is a racemate or racemic mixture?
A mixture containing equal amounts of each enantiomers
Why are racemates/racemic mixtures not optically active?
Because the effects cancel each other out because there is an equal amount of each enantiomer
Why is it important to test the effects of both enantiomers of an optically active drug during drug trials?
Because in some optical isomers, one enantiomer is an effective drug, whilst the other may have toxic or harmful side effects e.g. Thalidomide
What is the functional group for the homologous series: Nitriles
R - C (Triple Bond) H
