Organic Chemistry I: Exam 1 & 2 Concepts

Electronegativity Order (Common Atoms)

F > O > Cl/N > Br > I > C > H > P > Si

Equilibrium Acid-Base Direction

Equilibrium always favors the side of the weaker acid (higher pKa).

Alkyne Triple Bond Composition

One sigma (σ) bond and two pi (π) bonds.

H-Bond Donor vs. Acceptor

Donor: H attached to O, N, or F. Acceptor: Lone pair on O, N, or F.

Lewis Acid vs. Lewis Base

Lewis Acid: Electron pair acceptor. Lewis Base: Electron pair donor.

Ring Strain Factors

Angle strain (deviation from ideal hybridization angles) and torsional strain (eclipsing interactions).

Cycloalkane Stability Order

Cyclohexane (most stable) > Cyclopentane > Cyclobutane > Cyclopropane (least stable).

Optical Activity

Chiral molecules rotate plane-polarized light by a discrete angle called specific rotation.

Three Steps of Radical Mechanisms

1. Initiation, 2. Propagation, 3. Termination.

Two Main Reaction Types of Alkanes

Combustion and Radical Halogenation.

Chair Conformation Stability Rule

Equatorial substituents are more stable than axial substituents due to reduced 1,3-diaxial interactions.

Enantiomers

Non-superimposable mirror images; they have opposite configurations at all chiral centers.

Diastereomers

Non-superimposable, non-mirror image stereoisomers; they differ at some but not all chiral centers.

Constitutional Isomers

Molecules with the same molecular formula but different connectivity of atoms.

Newman Projection: Gauche vs. Anti

Gauche: 60° dihedral angle between large groups. Anti: 180° dihedral angle (more stable).

Spontaneous at All Temperatures (Thermodynamics)

ΔH is negative (exothermic) and ΔS is positive (entropy increases).

Electron Pushing Arrow Direction

Arrows start at an electron source (nucleophile/lone pair/bond) and point to an electron sink (electrophile).

Nucleophile vs. Electrophile Roles

Nucleophile: Electron-rich species (donates electrons). Electrophile: Electron-poor species (accepts electrons).