Isomerism Flashcards
What is structural isomerism?
Molecules which have the same molecular formula but different structural formula.
What are the three types of structural isomerism?
-Chain isomerism
-Positional isomerism
-Functional group isomerism
What is chain isomerism!
Molecules with the same molecular formula but a different arrangement of carbon atoms.
What is positional isomerism?
Molecules with the same molecular formula but which have the functional group in different positions in the molecules. e.g. butan-1-ol and butan-2-ol. Both have OH group but just on a different carbon.
What is functional group isomerism?
Molecules with the same molecular formula but different functional groups.
Functional groups include: OH groups of alcohol. NH2 group of amines. COOH group of carboxylic acids
What can show functional isomerism?
Cycloalkanes and alkenes.
What are stereoisomers?
Molecules with the same structural formula but a different arrangement of atoms in space.
Why do stereoisomers occur?
The C=C bond restricts rotation
Each C on C=C has two different groups.
Draw the Cis trans / EZ isomers for CHCl=CHCl
Cis isomer: Trans isomer:
Cl- -Cl Cl- -H
C=C C=C
H- -H H- -Cl
Draw the cis trans E/Z isomers for CHF=CHF
Cis isomer: Trans isomer:
H- -H H- -F
C=C C=C
F- -F F- -H
Draw the cis trans E/Z isomers for CFBr=CFBr
Cis isomer: Trans isomer:
F- -F. F- -Br
C=C. C=C
Br- -Br. Br- -F
What happens in Sp3 hybridisation for Methane? CH4. 1s2 2s2 2p2
-One s and 3p orbitals combine
-The s orbital moves up (increase energy)
-The 3 p orbitals all decrease in energy
-All orbitals have 1 electron in at the end
-Makes four single bonds.
-This makes 4 sp3 orbitals
-No double bonds because there are no electrons in the P orbital (top row)
What is the bond angle and molecular shape for Sp3 hybridisation?
109.5 degrees
Tetrahedral
What happens during sp2 hybridisation in Ethene C2H4.
-1s and 2p orbitals combine
-The s orbital moves up (increase energy)
-The 2 orbitals move down (decrease energy)
-All orbitals contain one electron
-This makes three sp2 hybrid orbitals
-there are 3 sigma bonds and 1pi bond because there was 1 spare P orbital
What happens during Sp hybridisation?
-1s and 1p orbital combine.
-This makes 2 sp hybrid orbitals so 2 sigma (single) bonds are formed.
-But there are 2 spare p orbitals on the top
row so this forms 2 Pi bonds.
-TRIPLE BOND IS FORMED
What is the bond angle and molecular shape of Sp2 hybridisation?
120 degrees
Tetrahedral
what is the bond angle and molecular shape of sp hybridisation?
180 degrees
Linear because it’s a line
☁️C☁️
