Organic Chemistry Foundations and Functional Groups

Comprehensive vocabulary flashcards covering the foundations of organic chemistry, nomenclature, stereochemistry, reactions, and laboratory identification tests.

Organic Chemistry

The study of compounds containing CARBON, hydrogen, halogens, oxygen, nitrogen, sulfur, and phosphorus.

Catenation

The ability of carbon to form multiple bonds with itself, resulting in straight, branched, or closed chains.

Sigma ($\sigma$) bond

A covalent bond formed by head-on or end-to-end overlap that lies along the bond axis; it is the strongest type and can exist independently.

Pi ($\pi$) bond

A covalent bond formed by sideways or side-to-side overlap that lies perpendicularly to the bond axis; it is weaker than a sigma bond and cannot exist independently.

Hybridization

The mixing of 2 or more nonequivalent atomic orbitals to form a new set of equivalent atomic orbitals.

sp3 Hybrid Orbital

An orbital with tetrahedral, bent, or trigonal pyramidal geometry and a bond angle of $109.5^{\circ}$; it forms the longest and strongest single bonds.

sp2 Hybrid Orbital

An orbital with trigonal planar geometry and a bond angle of $120^{\circ}$; it is associated with double bonds ($1 \sigma$, $1 \pi$).

sp Hybrid Orbital

An orbital with linear geometry and a bond angle of $180^{\circ}$; it is associated with triple bonds ($1 \sigma$, $2 \pi$).

Kekule Structure

A line-bond structure drawing that uses lines and dots to represent chemical bonds.

Lewis Structure

An electron-dot or Lewis-dot structure drawing that uses dots to show bonds between atoms.

Condensed Structure

A structural formula where single bonds are implied, hydrogens of the same atom are combined, and parentheses are used for branched parts.

Skeletal Structure

A bond-line or line-angle structure where C-H and C-C atoms are not shown, and only non-carbon atoms are displayed.

London dispersion / van der Waals

Intermolecular forces present in all molecules and atoms, specifically seen in alkanes, alkenes, and alkynes.

Hydrogen bond

The strongest intermolecular force present in molecules containing H bonded to F, O, N, or S; found in alcohols, carboxylic acids, amines, and amides.

Resonance

Also known as mesomerism; the continuous motion (delocalization) of pi or lone electrons across consecutive sp2 carbons which increases compound stability.

Huckel’s Rule

A qualification for aromaticity stating the number of pi electrons must equal $4n + 2$, where n is an integer.

Strain

Any unwanted disturbance or deviation from ideal bond angles.

Inductive Effect

The stability change caused by electronegativity; high electronegative atoms (H, S, O) decrease stability via electron withdrawing, while low electronegative atoms (alkyl groups) increase stability via electron donating.

Stereochemistry

The study of the spatial or three-dimensional (3D) arrangement of atoms in a molecule and their effects on properties.

Isomerism

Compounds that share the same chemical formula but have different structures.

Enantiomers

Stereoisomers that are non-superimposable mirror images.

Epimers

Optical isomers that are the same in all positions except for one carbon.

Anomers

Optical isomers that only differ in the configuration of the carbonyl carbon.

Meso Compounds

Compounds that have superimposable mirror images and do not have enantiomers.

Geometric Isomers

Also known as cis-trans isomers; categorized as cis-trans for similar substituents and E/Z for different substituents.

Anti-staggered Conformation

The most stable acyclic conformation where the two largest groups are opposite each other at a $180^{\circ}$ angle.

Electrophile (E+)

An "electron-loving," electron-poor species that attacks atoms with a high electron density (negative charge).

Nucleophile (Nu-)

A "nucleus-loving," electron-rich species that attacks atoms with a positive charge.

Reduction

A process involving the gain of an electron, the formation of a C-H bond, or the loss of a C-O bond.

Oxidation

A process involving the loss of an electron, the loss of a C-H bond, or the formation of a C-O bond (or equivalent).

Alkanes

Saturated aliphatic hydrocarbons known as Paraffins containing only single bonds with the formula $C_n H_{2n+2}$.

Alkenes

Unsaturated aliphatic hydrocarbons known as Olefins containing double bonds with the formula $C_n H_{2n}$.

Alkynes

Unsaturated aliphatic hydrocarbons known as Acetylene containing triple bonds with the formula $C_n H_{2n-2}$.

Markovnikov’s Rule

A rule used in addition reactions (like hydrohalogenation) stating the nucleophile attaches to the carbon with fewer H atoms and the H attaches to the carbon with more H atoms.

Zaitsev’s Rule

A principle used in elimination reactions (dehydrohalogenation and dehydration) to determine the major product.

Oxalic acid

The simplest dicarboxylic acid having 2 carbon atoms (Mnemonic: Oh).

Saponification

A reaction involving the hydrolysis of an ester with NaOH to produce soap and an alcohol.

Bromine Test

A test for unsaturated compounds where the disappearance of the orange color of bromine in $CCl_4$ indicates a positive result.

Beilstein Test

A test for halogenated compounds using a copper wire and flame; a green flame indicates a positive result for alkyl halides.

Lucas Test

A test for alcohols using zinc chloride in HCl; a positive result is indicated by the formation of two immiscible layers (speed: $3^{\circ} > 2^{\circ} > 1^{\circ}$).

Tollen’s Test

A test for reducing compounds (aldehydes) using ammoniacal silver nitrate; a positive result is the formation of a silver mirror.

Fehling’s Test

A test for reducing compounds using Fehling’s A ($CuSO_4$) and Fehling’s B (Na K tartrate); a positive result is a red precipitate.