B6

What is a chiral center?,"

An atom, such as carbon, with four different groups bonded to it."

How do you determine if a carbon in a structure like CH3​−CH2​−CH3​ is chiral or achiral?,"

It is achiral because it does not have four different atoms or groups bonded to the carbon (e.g., CH2​ has two hydrogens)."

How do you determine if the carbon in CH3​−CH(Cl)−Br is chiral or achiral?,"

It is chiral because it has a different group attached to the carbon (H, Cl, Br, CH3​)."

How do you determine if a carbon in CH3​−CH2​−C(=O)CH3​ is chiral or achiral?,"

It is achiral because it only has 3 atoms/groups bonded to the carbon (The carbon is sp2 hybridized in the C=O group, but the CH2​ is achiral)."

What are enantiomers?,

Stereoisomers that differ in absolute configuration at ALL chiral centers.

Do enantiomers have a mirror image?,

Yes.

Are enantiomers superimposable?,

No.

Are enantiomers optically active?,

Yes.

What are diastereomers?,

Stereoisomers that differ in at AT LEAST ONE but NOT all chiral centers.

Do diastereomers have a mirror image?,

No.

Are diastereomers superimposable?,

No.

Are diastereomers optically active?,

Yes.

What are epimers?,"

Diastereomers that differ in ONLY ONE chiral center (e.g., C2-epimers, C4-epimers)."

What are Meso compounds?,

Optically inactive compounds due to symmetry (cannot rotate the plane polarized light).

Do Meso compounds have a mirror image?,

Yes.

Are Meso compounds superimposable?,

Yes.

Are Meso compounds optically active?,

No.

Give an example of a simple Meso compound structure.,

Tartaric acid (with 2 chiral centers and a plane of symmetry).

What is Racemization?,

Process of changing from an optically active compound into a racemic compound (equal amounts of two isomers) or an optically inactive compound.

What is Resonance/Delocalization?,"

Delocalized electrons do not belong to a single atom, nor are they confined to a bond between two atoms (they have no permanent address)."

What is the effect of Resonance/Delocalization on a molecule's properties?,

Effect is ↑ stability and ↑ acidity.

What is the Inductive Effect?,"

Inducing polarity, caused by the electron-withdrawing or electron-donating nature of groups."

What are Electron Withdrawing Groups (EWGs)?,"

Groups that are ""pulling"" of electrons, such as −COOH, −SO3​H, −NO2​, −F, −Cl, −Br, −I."

What is the effect of Electron Withdrawing Groups (EWGs) on acidity?,

↑ acidity.

What is the relative stability trend for carbanions (negative charge) based on the number of alkyl groups?,

Methyl > 1∘ > 2∘ > 3∘ (less alkyl groups are more stable).

What are Electron Donating Groups (EDGs)?,"

Groups that are ""pushing"" of electrons, such as −OH, −NH2​, −OR, −R (EXCEPT Halogens)."

What is the effect of Electron Donating Groups (EDGs) on acidity?,

↓ acidity.

What is the relative stability trend for carbocations (positive charge) based on the number of alkyl groups?,

3∘ > 2∘ > 1∘ > methyl (more alkyl groups are more stable).
"

For Hydrides and Hydrogen Halides with similar atomic size, how does electronegativity affect acidity?",

↑ Electronegativity = ↑ acidity.
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For elements with similar atomic size, arrange CH4​, NH3​, H2​O, and HF in order of increasing acidity.",

CH4​ < NH3​ < H2​O < HF.
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For Hydrides and Hydrogen Halides with different atomic size, how does atomic size affect acidity?",

Size is MORE important than electronegativity. ↑ Atomic Size = ↑ Acidity.
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For elements with different atomic size, arrange HF, HCl, HBr, and HI in order of increasing acidity.",

HF < HCl < HBr < HI (HI is the most acidic).
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For Carboxylic Acids, how does the inductive electron withdrawal effect (electronegativity) of a substituent affect acidity?","

↑ Electron-withdrawing (electronegativity) = ↑ Acidity (e.g., F is most acidic)."
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For Carboxylic Acids, how does the distance of an electron-withdrawing substituent to the oxygen atom affect acidity?",

Substituent nearer to the oxygen atom = ↑ Acidity (lower pKa