Lewis Structures and Bonding Vocabulary

Vocabulary flashcards covering key terms related to valence, Lewis structures, bonding types, octet rules, lone pairs, and formal charge.

Valence

The combining capacity of an atom, often described by the outermost electrons that participate in bonding.

Valence electrons

Electrons in the outermost shell that participate in bonding and determine an atom's valence.

Covalent bond

A bond formed when two atoms share a pair of electrons.

Single bond

A covalent bond consisting of one shared pair of electrons (two electrons).

Double bond

A covalent bond consisting of two shared pairs of electrons (four electrons).

Triple bond

A covalent bond consisting of three shared pairs of electrons (six electrons).

Bond order

The number of shared electron pairs between two atoms; 1 for a single bond, 2 for a double bond, 3 for a triple bond.

Lone pair

A pair of nonbonding electrons localized on a single atom in a Lewis structure.

Lewis structure

A diagram showing atoms, covalent bonds, and lone pairs to represent a molecule's connectivity and electron distribution.

Octet rule

Most main-group atoms aim to have eight electrons in their valence shell (two for hydrogen) in stable structures.

Central atom

The atom in a Lewis structure that other atoms bond to; usually the least electronegative among bonded atoms.

Central-atom exceptions

Hydrogen and fluorine never sit in the center; oxygen is rarely central.

Second-row octet limit

Period 2 elements (Li–F) generally cannot have more than eight electrons around them; no expanded octet.

Nonbonding electrons

Electrons not involved in bonding; also called lone pairs.

Bonding electrons

Electrons that participate in covalent bonds between atoms.

Formal charge

The hypothetical charge on an atom in a Lewis structure if bonding electrons were shared equally.

Formal charge formula

Formal charge = valence electrons − nonbonding electrons − (bonding electrons)/2.

Polyatomic ion

A charged group of covalently bonded atoms that acts as a single unit in reactions.

Electron counting for ions

To build Lewis structures for ions, adjust the total valence electrons by subtracting the charge for cations and adding the charge for anions.