Chapter 1-8 Organic Chemistry: Lewis Structures, Nomenclature, and Basic Concepts

Vocabulary flashcards covering Lewis structures, valence electrons, octet rule, hydrocarbons, line vs Lewis structures, heteroatoms, and basic nomenclature concepts from the notes.

Valence electrons

Electrons in the outermost shell that participate in bonding.

Octet rule

Most elements prefer to have eight electrons in their outer shell to be stable; hydrogen needs two.

Hydrogen exception (duet)

Hydrogen is stable with 2 electrons in its outer shell (duet).

Lewis structure

A representation showing bonds (lines) and valence electrons (dots); an intermediate between line and dot structures.

Molecular formula

Shows the total numbers of carbon, hydrogen, and heteroatoms in a molecule, usually with subscripts.

Line structure

A simplified structural formula using bonds; atoms are implied at vertices and most hydrogens on carbons are not shown.

Heteroatom

An atom other than carbon or hydrogen in an organic molecule (e.g., O, N, S, P).

Halogens

Group with seven valence electrons that typically forms one bond (F, Cl, Br, I).

Noble gases

18th column elements with full outer shells; generally nonreactive.

Valence electron concept in main-group elements

Valence electrons roughly equal the group number; determines bonding in organic molecules.

Methane (CH4)

A saturated alkane with one carbon bonded to four hydrogens; tetrahedral geometry; octet satisfied.

Central atom

The atom in a molecule that forms the maximum number of bonds (e.g., carbon in CH4).

Alkane formula

CnH2n+2; saturated hydrocarbons with only single bonds.

Unsaturated compounds

Molecules with double or triple bonds (not alkanes).

Double bond

Two shared electron pairs between two atoms; represented by two lines (e.g., C=O).

Ketone

A carbonyl compound where the carbonyl carbon is bonded to two other carbons (R-CO-R).

Aldehyde

A carbonyl compound where the carbonyl carbon is bonded to one carbon and one hydrogen (R-CHO).

Carboxylic acid

A carbonyl group with an –OH attached (often written as –COOH); highly reactive.

Lewis vs line structure comparison

Lewis shows all bonds and lone pairs; line structure shows bonds only and omits most hydrogens.

Lone pairs

Nonbonding electron pairs on atoms as shown in Lewis structures.

Methyl and Ethyl groups

Methyl = CH3; Ethyl = C2H5; substituent names ending in -yl when attached to a parent chain.

IUPAC suffix -ane

Suffix used for alkanes (e.g., methane, ethane, propane) indicating single bonds.

Substituent naming with -yl

Groups attached as substituents (methyl, ethyl, propyl, etc.) with the -yl suffix.

Primary/Secondary/Tertiary/Quaternary carbons

Classifications by number of carbon neighbors: primary (1), secondary (2), tertiary (3), quaternary (4).

Cycloalkanes

Saturated cyclic hydrocarbons (cyclopropane, cyclobutane, cyclopentane, cyclohexane).

Cyclo- prefix

Prefix used to indicate a cyclic structure (e.g., cyclohexane).

Geometric rules for carbon bonding

Carbon with four bonds is tetrahedral; three bonds is trigonal; two bonds is linear.

Charge on carbon: carbocation and carbanion

Carbocation: carbon with a positive charge; Carbanion: carbon with a negative charge.

Hydrogen placement in line structures

Hydrogens attached to heteroatoms are shown; hydrogens attached to carbons are not.

Functional groups and carbonyls

C=O groups define carbonyl compounds; specific arrangements (R-CO-R vs R-CHO) determine ketones vs aldehydes.

Cyclopropane naming

Three-membered cycloalkane; part of the cycloalkane family (cyclo- prefix).

Cyclic vs acyclic naming

Cyclic alkanes use the cyclo- prefix; acyclic alkanes do not.

Structure-to-name link (example)

Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10) illustrate -ane naming; methyl/ethyl as substituents illustrate -yl naming.

Valence electron distribution and octet satisfaction

Count valence electrons, distribute to satisfy octets, form bonds (single/double/triple) accordingly.