Chemical Bonding, Molecular Geometry, and Intermolecular Forces

Vocabulary practice flashcards reviewing chemical bonding types, VSEPR molecular shapes, element classifications, and intermolecular forces based on unit lecture notes.

Chemical Bond

A lasting attraction between atoms or ions that enables the formation of chemical compounds.

Ionic Bond

An electrostatic force of attraction between oppositely charged ions, formed when metals lose valence electrons to become positive ions ($+\text{ ions}$) and nonmetals gain valence electrons to become negative ions ($-\text{ ions}$).

Covalent Bond

A chemical bond formed by a shared pair of valence electrons so that atoms achieve a complete set of valence electrons.

Single Bond

A covalent bond involving $1\text{ pair of e}^-$ shared between two atoms.

Double Bond

A covalent bond involving $2\text{ pair of e}^-$ shared between two atoms.

Triple Bond

A covalent bond involving $3\text{ pair of e}^-$ shared between two atoms.

Valence Electrons

Outermost electrons ($s$ and $p$) of an atom that can be lost, gained, or shared as a chemical bond is formed.

Lewis Dot Structure

Diagrams that represent the valence electrons of atoms, molecules, or polyatomic ions using dots around element symbols.

Metallic Bonding

A chemical bond between atoms in a metallic element, formed by valence electrons moving freely through a metal lattice (a sea of mobile delocalized electrons).

Polyatomic Ion

A covalently bonded set of two or more atoms that behaves as a single unit and possesses a positive ($+$) or negative ($-$) charge.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory; a model used to predict the shape of molecules based on the assumption that valence electron pairs surrounding central atoms arrange themselves to minimize repulsion.

Linear Shape

A molecular shape occurring when only $2$ atoms are bonded together, or when $1$ central atom is bonded to $2$ other atoms with no paired valence electrons on the central atom (bond angle $180^\text{o}$).

Bent Shape

A molecular shape featuring $1$ central atom bonded to $2$ other atoms plus unbonded paired valence electrons on the central atom (e.g., $\text{H}_2\text{O}$ with a bond angle of $104.5^\text{o}$).

Trigonal Planar Shape

A molecular shape with $1$ central atom bonded to $3$ other atoms and no paired valence electrons on the central atom, serving as an exception to the octet rule (e.g., Boron compounds like $\text{BF}_3$).

Trigonal Pyramidal Shape

A molecular shape featuring $1$ central atom bonded to $3$ other atoms plus a pair of unbonded valence electrons on the central atom (e.g., $\text{NH}_3$).

Tetrahedral Shape

A molecular shape featuring $1$ central atom bonded to $4$ other atoms with no unbonded electron pairs on the central atom (e.g., $\text{CH}_4$ with a bond angle of $109.5^\text{o}$).

Metal

Elements that are mostly solid at room temperature, hard, shiny, malleable, ductile, and possess good electrical and thermal conductivity.

Nonmetal

Elements that lack metallic properties and are typically poor conductors of heat and electricity.

Metalloid

An element with properties in between those of metals and nonmetals; physically shiny, brittle solids with intermediate to relatively good electrical conductivity.

Coordinate Covalent Bond

A type of covalent bond in which the shared pair of electrons comes entirely from one of the bonding atoms.

Network Covalent Bond

A continuous network of covalent bonds extending throughout a solid material (macromolecule) without individual molecules, characterized by extreme hardness, brittleness, high melting points ($>1,000^\text{o}\text{C}$ or $1,800^\text{o}\text{F}$), and non-conductivity.

Intramolecular Forces

Forces that hold atoms together within a molecule, such as ionic or covalent bonds.

Intermolecular Forces

Electrostatic forces that exist between adjacent molecules, ions, or atoms.

Dipole-Dipole Forces

Attractive intermolecular forces between the positive partial charge end of one polar molecule and the negative partial charge end of another polar molecule.

Hydrogen Bonding

An electrostatic force of attraction between a hydrogen ($\text{H}$) atom covalently bound to a highly electronegative atom (generally nitrogen $\text{N}$, oxygen $\text{O}$, or fluorine $\text{F}$) and a neighboring electronegative atom.

London Dispersion Forces

The weakest intermolecular force; a temporary attractive force between nonpolar atoms or molecules that results when instantaneous uneven electron distribution induces temporary dipoles in adjacent atoms.

Dipole-Induced Dipole Forces

Weak intermolecular forces that occur when an ion or polar molecule with a permanent dipole induces a temporary dipole in a neighboring nonpolar atom or molecule.

Ion-Dipole Forces

An attractive intermolecular force resulting from electrostatic attraction between a charged ion and a neutral polar molecule with a dipole.