Hydrocarbons and Organic Compounds Unit Review

Flashcards covering key vocabulary, definitions, and concepts from the lecture notes on hydrocarbons including alkanes, alkenes, bonding, structure, and isomerism.

Hydrocarbons

Compounds that contain only carbon and hydrogen atoms.

Alkanes

Saturated hydrocarbons that contain only carbon-hydrogen and carbon-carbon single bonds. They have the general formula CnH2n+2.

Alkenes

Unsaturated hydrocarbons containing at least one C=C double bond in the molecule. They have the general formula CnH2n.

IUPAC

International Union of Pure and Applied Chemistry, a group that standardizes chemical nomenclature rules.

Lewis Structure

A convenient way to show the covalent bonding in organic molecules where each valence electron is represented by a dot, and a bonding pair by a pair of dots or a straight line.

Condensed Structural Formula

Shows what atoms are present and how they are connected, without explicitly showing all chemical bonds.

Bond-line Structure

Simplified drawings that use lines to represent atoms and bonds, where carbon atoms are at vertices or ends of lines, and hydrogen atoms bonded to carbon are usually not shown.

Covalent Bonding

A type of bonding in organic compounds involving the sharing of electrons between atoms, typically following the Octet Rule.

Octet Rule

States that atoms prefer to have a filled shell of eight valence (outermost) electrons when forming covalent bonds.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory, which states that bonding and non-bonding electron pairs around a central atom repel each other until they are separated by the largest possible angles, determining molecular geometry.

sp³ Hybrid Orbitals

Hybrid orbitals used by carbon atoms in alkanes, derived from one s and three p atomic orbitals, resulting in four identical orbitals with tetrahedral geometry.

Sigma Bond ("σ" bond)

A type of covalent bond formed when two atomic orbitals overlap head-on, building up electron density between the two nuclei.

Nonbonding Electrons (Lone Pairs)

Electrons not used in bonding, often found on atoms like nitrogen, oxygen, and halogens in organic compounds.

Main Chain (Alkanes)

The longest continuous chain of carbon atoms in an alkane, which forms the base name of the compound according to IUPAC rules.

Substituents

Groups attached to the main carbon chain of a compound.

Alkyl Groups

Substituent groups derived from alkanes by removing one hydrogen atom, named by replacing the 'ane' ending of the alkane name with 'yl'.

Alkyl Halides

Alkanes where one or more hydrogen atoms are replaced with halogens (fluoro, chloro, bromo, iodo).

Degree of Substitution

A classification (primary, secondary, tertiary, quaternary) describing the number of carbon atoms connected to a carbon atom of interest in alkanes and alkyl halides.

Cycloalkanes

Alkanes that contain a ring of carbon atoms, having the general formula CnH2n.

Isomers

Different compounds that have the same molecular formula.

Constitutional Isomers (Structural Isomers)

Isomers that have the same molecular formula but their atoms are connected in a different order.

Stereoisomers (Geometric Isomers)

Compounds that have the same molecular formula and connectivity, but differ only in the way their atoms are oriented in space.

cis-trans Isomerism (Cycloalkanes)

Describes the relative position of two substituents on different carbons in a cycloalkane ring; 'cis' means on the same side, 'trans' means on opposite sides.

sp² Hybrid Orbitals

Hybrid orbitals used by carbon atoms in alkenes, derived from one s and two p atomic orbitals, forming three identical orbitals with trigonal planar arrangement.

Pi Bond ("π" bond)

A type of covalent bond in alkenes formed by the side-by-side overlap of unhybridized p orbitals, located above and below the plane of the sigma bond.

cis Isomer (Alkenes)

A stereoisomer of an alkene where similar groups are on the same side of the double bond.

trans Isomer (Alkenes)

A stereoisomer of an alkene where similar groups are on opposite sides of the double bond.

E-Z System

A system of nomenclature used for trisubstituted and tetrasubstituted alkenes to denote stereochemistry, where 'E' (entgegen) means opposite sides and 'Z' (zusammen) means same side for highest priority groups.