Orbitals + Hybridization
S orbital |
Sphere, low energy, one orbital, holds up to 2e |
P orbital |
Dumbell, high energy, 3 orbitals, can hold up to 6e |
Hybridization |
The hybridization is sp( # different e- fields -1) |
Lewis structure + Formal charge
1. Count ve- |
keep in mind ions add for negative subtract for positive |
2. placement of atoms |
H are terminal, C usually in center |
3. Form bonds and create strcutre |
Aknowledge resonance structures |
Formal charge |
an atom is negative if it has an additonal electron and positive if it is missing electrons |
Nucleophilic center |
negative |
Electrophilic center |
positive |
Conjugate acid-> base pairs
Stronger acid |
weaker conjugate base |
Weaker acid |
stronger conjugate base |
Comparing Acidities
1. Resonance |
If the conjugate base is more stabilized the acid is more acidic |
Which proton is more acidic |
The one with a conjugate base with resonance |
2.Inductive effects |
More electronegative atoms= more acidic |
3. Hybridization |
CHsp is more acidic than CH sp3 |
4. Charge |
Positively charged acids are more acidic. |
SN1 reaction
Weak nucleophile and weak base |
SN1, E1 |
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H2O, ROH |
Strong base, bad nucleophile |
E2 |
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t-But, LDA, DBN, DBU |
Strong nucleophile, weak base |
SN2 |
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I-,Cl-,Br-,N3, CN-,HS-,RS- |
Strong nucleophile, strong base |
SN2, E2 |
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HO-, RO-, -NH2,-OR |
Hydrocarbons + Halides
Alkane |
C-C |
Alkene |
C=C |
Alkyne |
C---C |
Halide |
R-X (X=Cl, Br, I,F) |
-Primary halide |
C attatched to H is attatched to 1 other C |
-Secondary halide |
C attatched to H is attatched to 2 other carbons |
-Tertiary halide |
C attatched to H is attatched to 3 other carbons |
Constitutional Isomers
Same molecular formula |
Different Connectivity |
Constitutional isomers often have |
-Always have same formula |
-different branching |
-Different C skeleton |
-Functional group in different location |
-Different C chain length |
Ex |
CH3-O-CH3 vs CH3-CH2-OH |
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Molecular geometry
Sigma bonds |
all single bonds, stronger, usually allows rotation, axial overlap |
Pi bonds |
double and triple bonds, slightly longer, restricted rotation creating cis and trans |
Resonance stability
More bonds |
More stable |
Negative charges on |
more electronegative atoms is more stable |
Positive charges |
on less electronegative atoms is more stable |
Less formal charges |
More stable |
Avoid |
like charges next to each other |
Acidity trends
1. (most acidic) |
Strong acids |
2. |
Carboxyllic acid |
3. |
Phenol |
4. |
Alcohol |
5. |
Water |
6. |
Amines |
7. |
Alkanes/Alkenes/Alkynes |
Pka as acidity decreases |
increases |
Pka vs acidity |
inverse relationship |
Nucleophile vs Base
Nucleophile |
Donates a pair of electrons |
| |
Attacks electrophile |
| |
Causes substitution reactions |
Nucleophilicity |
kinetic (how fast it attacks C) |
Base |
Removes a proton |
| |
Causes Elimination reactions |
Basicity |
thermodynamics, how badly it wants a proton |
- |
Negative charge |
Strong nucleophile, stronger base |
Less electronegative |
Better nucleophile |
Larger |
Better nucleophile |
Smaller |
Stronger Base |
Steric hinderance for nucleophiles |
bulky bases are bad nucleophiles |
Has resonance |
weaker nucleophile |
Oxygen, Nitrogen and other functional groups
Alcohol |
R-OH |
Phenol |
OH on aromatic ring |
Esther |
R-O-R |
Carbonyl-containing groups |
O=C-R, R |
Aldehyde |
O=C-H, -R |
Ketone |
O=C-R -R |
Carboxyllic acid |
O=C-R, -OH |
Esther |
Amide |
C- |
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