3.1 Intro Flashcards
What are isomers?
Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space
What are structural isomers?
In structural isomers, the atoms are arranged in a completely different order.
What are the types of structural isomerism?
- Chain isomerism
- position isomerism
- functional group isomerism
How do chain isomers arise?
Because of the possibility of branching in carbon chains.
How do position isomers arise?
In position isomerism the basic carbon chain remains the same, but groups are moved around on that skeleton.
Give an example of position isomerism
CH3CH2CH2Br (1-bromopropane) vs CH3CHBrCH3 (2-bromopropane)
How do functional group isomers arise?
Isomers belong to different homologous series but have the same formula
What is geometric isomerism?
Geometric isomerism is a form of stereoisomerism
What are stereoisomers?
When the atoms making up the isomers are joined in the same order, but have a different spatial arrangement.
How do geometric isomers arise?
They arise due to the locked rotation around a double C=C bond.
What are optical isomers?
Two enantiomers (molecules) that are mirror images of each other but are non-superimposable (not identical)
What causes optical isomers?
When there are 4 different substituents bonded to a central carbon atom
What is a racemic/racemate mixture?
A mixture that contains equal amounts of both enantiomers. They are not optically active as they cancel each other out.
What do optical isomers do to light?
Optical isomers interact with polarised light, rotating it either clockwise (a + isomer) or anti-clockwise (a - isomer)
