Chem 4:4 - Nomenclature and Isomerism Flashcards
What are structural isomers?
Structures with the same molecular formula but different structural arrangements of atoms
What are the 3 types of structural isomers?
Chain isomers
Positional isomers
Functional Group Isomers
What are chain isomers ?
Different arrangement of the carbon skeleton,
some straight chains and some branched chains
What are positional isomers?
Same skeletons and atoms but FG in different place
What is a functional group isomer?
Same atoms arranged into different functional groups
What is steroisomerism?
Same structural formula but a different arrangement of atoms in space
In terms of rotation around bonds, how do single and double bonds work?
There is rotation around a single bond but no rotation round a double bond
What does this no rotation round a double bond mean?
This means that some alkene are steroisomers
When does stereoisomerism occur in an alkene
When the carbon atoms in the double bond hand 2 different groups attatched.
What do you get with stereoisomerism in alkenes
an E and Z isomer
What is optical isomerism?
A type of stereoisomerism
A chiral carbon has 4 different groups attatched to it
It is possible to make 2 different molecules around this carbon to make OPTICAL ISOMERS or ENANTIOMERS.
What shape will an optical isomer be?
Tetrahedral
In terms of light,, what do optical isomers do ?
Rotate the plane of polarised light
What do the positive and negative isomers do to the light
And what does normal light do ?
+ve isomer rotates it in the clockwise direction
-ve isomers rotate light in the anticlockwise direction
Normal light vibrates it in all directions
What is a racemate or racemic mixture ?
Contains equal quantities of each enantiomer of an optically active compound
