Unit 2: Molecular and Ionic Compound Structure and Properties (copy)

Electronegativity

The tendency of an atom to attract shared electrons.

Ionic Bonding

The model used when electrons are transferred between atoms, resulting in a lattice of cations and anions.

Covalent Bonding

The model used when atoms share electrons to form molecules or networks.

Metallic Bonding

The model where valence electrons are delocalized across many atoms, contributing to conductivity.

Potential Energy Well

A graphical representation of how potential energy changes with internuclear distance, showing stability at equilibrium.

Coulomb's Law

Describes the electrostatic force between two charged particles, proportional to the product of their charges and inversely proportional to the square of the distance between them.

Bond Energy

The energy required to break one mole of a specific bond type in the gas phase.

Lattice Energy

The energy released when gaseous ions form an ionic solid or the energy required to separate the solid into gaseous ions.

Resonance Structures

Different Lewis structures for the same molecule or ion showing varying electron placement but identical atom placement.

Formal Charge (FC)

A bookkeeping method for accounting the distribution of electrons in a molecule, calculated as FC = V - N - B/2.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory; predicts molecular shape based on the repulsion between electron pairs.

Electron Domains

Regions around a central atom that can be bonds or lone pairs, counted to determine geometry.

Sigma Bond

A bond formed from end-to-end overlap of orbitals along the internuclear axis.

Pi Bond

A bond formed from side-by-side overlap of unhybridized p orbitals.

Molecular Polarity

Determined by the vector sum of bond dipoles, which indicates the overall dipole moment of a molecule.

Intermolecular Forces

Forces that hold molecules together, affecting properties like melting points and boiling points.

Conductivity

The ability of a substance to conduct electricity, which depends on the mobility of charged particles.

Covalent Network Solids

Solids where atoms are tightly bonded in a continuous network, exhibiting very high melting points and hardness.

Ionic Compounds

Compounds formed from cations and anions that typically have high melting points and conduct electricity when molten or dissolved.

Molecular Solids

Solids composed of neutral molecules held together by weak intermolecular forces, generally having lower melting points.

Alloys

Mixtures of elements with metallic properties that can enhance strength and hardness by disrupting the lattice structure.

Electron-Sea Model

A model of metallic bonding where electrons are delocalized, allowing for conductivity and malleability.

Lewis Structure

A diagram representing the valence electrons in a molecule, used to predict connectivity and bonding.