ISOMERS Flashcards
Compounds having the same molecular formula and same molecular weight but different structural formula, thus differ in physical and chemical properties.
Isomers
Isomer compounds have the same what?
Molecular formula and molecular weight
Isomer compounds differ in what?
Physical and Chemical properties
Isomers have different what?
Structural formula
Molecular Formula is also known as?
Chemical Formula
It gives the proportions of atoms which is present in the molecule or compound.
Molecular Formula (Chemical Formula)
It shows different graphic representation of the molecule and compound.
Structural Formula
Structural Formula types
Expanded, Condensed, Skeletal
2 Dimensional
Structural
3 Dimensional
Stereo
Subtypes of Structural
Chain
Positional
Functional Metamerism
Tautomerism
Ring-chain
Subtypes of Stereo
Geometric
Optical
AKA Constitutional Isomers
Structural Isomerism
Compounds which have the same molecular formula but differ in their structure.
Structural Isomers
Simplest Hydrocarbons
CH4 (Methane)
CH3CH3 (Ethane)
CH3CH2CH3 (Propane)
Which hydrocarbons doesn’t have constitutional isomers?
Simplest hydrocarbons
This hydrocarbon has constitutional isomers.
C4H10 (Butane)
CH4
Methane
CH3CH3
Ethane
CH3CH2CH3
Propane
C4H10
Butane
meaning of ( n ) in n-butane
normal and straight chain
prefix “iso” is used when?
the structure is branched
iso meaning
isomer
isomer is used usually on
2-methylalkanes
This isomers differ in the chain of the carbon atoms.
Chain Isomers
other name of isobutane
2-methylpropane
prefix “neo” is used when
second to the last carbon is tri-substituted
IUPAC name of neopentane
2,2-dimethylpropane
These isomers differ in the type of functional group.
Functional Isomers
Has the same molecular formula but differs in functional group.
Functional Isomers
These isomers differ in the attachment of the functional group to the chain at different positions.
Positional Isomers
This type of isomerism arises due to the presence of different alkyl chains on each side of the functional group.
Metamers
It is a rare type of isomerism and is generally limited to molecules that contain a divalent atom (such as sulfur or oxygen), surrounded by alkyl groups.
Metamers
Divalent atoms
Sulfur / Oxygen
Metamers examples
Ethers
Thioethers
Ketone
Isomer of the compound which only differs in the position of protons and electrons.
Tautomers
It occurs via an intramolecular proton transfer.
Tautomers
Tautomers important example is
Keto-enol tautomerism
⇌
reversible
Has carbonyl carbon.
Keto form
Has presence of double bond and hydroxyl group.
Enol form
Keto form is _____ stable?
More stable 99.9%
Enol form is ____ stable
less stable 0.001%