Isomerism Flashcards
What are isomers?
Isomers are molecules that have the same molecular formula but atoms arranged differently
How many types of isomerism are there?
What are the different types of isomerism?
There are two types of isomerism, being structural isomerism and stereoisomerism
What are structural isomers?
Structural isomers are organic compounds which have the same molecular formula but different structural formulae
There are three subdivisions within structural isomerism, what is the name of each subdivisions?
1* Positional isomerism
2* Functional group isomerism
3* Chain isomerism
What is positional isomerism?
Positional isomerism is when the same functional groups are attached to the main chain but at different points
What is functional group isomerism?
Functional group isomerism is when functional groups are changed on an organic compound. For example, changing an organic compound from being an alcohol (-ol) to an aldehyde (-al)
What is a feature of functional group isomerisms?
Functional group isomerism leads to having different physical and chemical properties
What is chain isomerism?
Chain isomerism is when there is a different arrangement of the hydrocarbon chain
What is stereoisomerism?
Stereoisomerism is when two (or more) compounds have the same structural formula
What are the two types of stereoisomerism?
There is E-Z isomerism and Optical isomerism
What does an E isomer show?
What does a Z isomer show?
An E isomer shows atoms or groups of atoms on the opposite sides of the C=C bond
A Z isomer shows atoms or groups of atoms on the same sides of the C=C bond
There is also the cis and trans naming system, what does the cis prefix represent when naming a isomer?
What does the trans prefix represent when naming a isomer?
Cis isomers represent isomers which have both functional groups on the same side above/below the carbon double bond
Trans isomers represent isomers which have the functional groups on opposite sides
There are E-Z notations and Cis/ Trans notations, what is each equivalent to?
E notations are equivalent to Trans notations
Z notations are equivalent to Cis notations
How do you deduce whether an isomer is an E or Z isomer?
An E isomer has the highest priority groups on the opposite sides of the C=C bond, having one above, one below
A Z isomer has the highest priority groups on the same sides of the C=C bond, having both either above or below the C=C bond
What set of rules can be applied to identifying E or Z isomers, and how can they be applied?
Cahn - Ingold - Prelog rules
1) You would look at the atoms directly attached to the carbon
2) Then the atom with the highest atomic number has the highest priority
