Organic Chemistry I - Structure, Bonding, and Stereochemistry (Fill-in-the-Blank)

A set of fill-in-the-blank flashcards covering key concepts from Structure & Bonding and Stereochemistry topics.

Stereochemistry is the study of the spatial arrangement of atoms in molecules and __.

stereoisomers

A chiral center is a carbon atom bonded to four different __.

substituents

Chiral molecules are non-superimposable on their mirror images because they contain at least one __ center.

chiral

R/S configuration: 1) Assign priorities using __.

atomic number

In R/S analysis, orient the molecule so the lowest priority group is in the __.

back

In R/S, the order 1→2→3 clockwise corresponds to the __ configuration.

R

In R/S, the order 1→2→3 counterclockwise corresponds to the __ configuration.

S

Enantiomers have identical physical properties except for optical __.

rotation

Enantiomers have opposite __ configurations at all chiral centers.

R/S

Diastereomers are not mirror images and differ in some, but not all, __ centers.

stereocenters

Meso compounds have stereocenters but are __ due to an internal plane of symmetry.

achiral

Clockwise rotation is dextrorotatory; counterclockwise rotation is levorotatory. The term for the clockwise rotation is __.

dextrorotatory

The number of stereocenters in 2,3-dibromobutane is __.

two

Lactic acid has a chiral center with configuration __.

S

Tartaric acid can be __ (meso or chiral).

meso

General structure of a carbonyl group is __ (R2C=O).

R2C=O

In carbonyl groups, the carbon bears a partial positive charge (δ+) and the oxygen bears a partial negative charge (δ−) due to __.

polarization

Aldehydes have the general formula __.

RCHO

Ketones have the general formula __.

RCOR'

Esters have the formula __.

RCOOR'

Amides have the formula __.

RCONH2

Acid chlorides have the formula __.

RCOCl

The carbonyl carbon is __ hybridized.

sp2

Resonance in carbonyls is represented by C=O ↔ C+–O− and helps explain why the carbonyl carbon is __ hybridized.

sp2

Nucleophilic addition to aldehydes and ketones proceeds via a __ intermediate.

tetrahedral

Hydration of aldehydes forms a __ (gem-diol).

gem-diol

Hemiacetal formation from RCHO + ROH gives a __.

hemiacetal

Acetal formation is catalyzed by an __; acetals are stable in base.

acid

Imine formation (Schiff base) from RCHO and R'NH2 yields an __.

imine

Reduction of aldehydes yields a alcohol; reduction of ketones yields a alcohol.

primary

Aldehydes are reduced to a __ alcohol by NaBH4 or LiAlH4.

primary

Ketones are reduced to a __ alcohol by NaBH4 or LiAlH4.

secondary

Aldehydes oxidize to __ acids; common reagents include Tollens', Jones, and KMnO4.

carboxylic

The aldol reaction forms a __ (β-hydroxy carbonyl).

beta-hydroxy carbonyl

Aldol condensation involves loss of __ to form a new C–C π bond.

water

Crossed aldol condensations require one aldehyde to be non-enolizable, i.e., lacking any __ on the alpha carbon.

alpha hydrogens

Intramolecular aldol reactions can form __ rings.

5- and 6-membered

The enolate is formed at the __ carbon.

alpha

Hybridization: sp is linear with __ electron groups.

2

sp2 is trigonal planar with __ electron groups.

3

sp3 is tetrahedral with __ electron groups.

4

Resonance structures show delocalization of electrons; the real molecule is a __.

resonance hybrid

NO3− shows resonance among three equivalent __.

structures

VSEPR predicts the geometry of NH3 as __.

trigonal pyramidal

Bond polarity arises from differences in __; a large ΔEN leads to a polar bond.

electronegativity

Molecular polarity depends on bond polarity and molecular __.

shape

Lewis structures follow the __ rule; exceptions include H, B, and expanded octets.

octet

Electrons occupy orbitals: s, p, d, f; valence electrons determine __ bonding behavior.

bonding