Isomers Flashcards
molecules with the same chemical formula but different arrangements of atoms
isomers
two main types of isomers
stereoisomers and structural isomers
Two or more molecules that have the same atoms, but the atoms are bonded together differently
structural isomers
Two or more molecules that have their atoms bonded in the same way, but the atoms are arranged differently in space
stereoisomers
The location (carbon) where the isomer occurs is
called
stereocentre/stereogenic centre
Two types of stereoisomers are
Geometric Isomers and Optical Isomers
These isomers can have very different physical properties, but tend to have the same chemical properties.
Geometric Isomers
The positioning of the groups around the C=C double bond allows alkenes to form stereoisomers.
alkene stereoisomers
isomer has similar groups on the same side of the double bond, it is called
cis isomer
isomer has similar groups on the opposite sides of the double bond, it is called
trans isomer
isomer has similar groups on the opposite sides of the double bond, it is called
trans isomer
Stereoisomerism can also occur in cyclic compounds.
cyclic stereoisomers
Molecules with NON-
SUPERIMPOSABLE mirror
images are
chiral
Molecules with
SUPERIMPOSABLE mirror
images are
achiral
chiral, in a chiral environment, they have different chemical properties, meaning diff effects
enantiomers
enantiomer whose optical activity rotates the light clockwise, dextrorotatory
(+)
enantiomer whose optical activity rotates the light counterclockwise, levorotary
(-)
formation of a racemic mixture of the enantiomers because of blood pH, they flip between r and s, causing side effects
racemization
comparison to glyceraldehyde
d vs l
If the priority of the substituent groups on the chiral carbon DECREASES in the CLOCKWISE direction, the enantiomer is
R
If the priority of the substituent groups on the chiral carbon DECREASES in the COUNTERCLOCKWISE direction,
S
examples of enantiomers
limonene (citrus), carvone (herbs)
If a molecule has more than one stereocentre, some of the isomers will be enantiomers, and those that aren’t (NOT mirror images) are
diastereomers
