Structure, Bonding and the Properties of Matter – Key Vocabulary

Vocabulary flashcards covering the essential terms and definitions from the lecture on chemical bonding, molecular and ionic structures, and related properties.

Molecule

A group of two or more atoms chemically bonded together by covalent bonds.

Covalent Bond

A strong bond formed when two non-metal atoms share a pair of electrons to achieve a full outer shell.

Dot-and-Cross Diagram

A model that represents covalent bonding by showing shared and unshared electrons as dots and crosses around atomic symbols.

Ion

An atom that has gained one or more electrons to become negatively charged or lost one or more electrons to become positively charged.

Ionic Bond

The electrostatic attraction between oppositely charged ions produced by electron transfer between a metal and a non-metal.

Electrostatic Attraction

The force that draws positive and negative charges together; responsible for both ionic bonds and the strength of covalent bonds.

Outer (Valence) Shell

The highest-energy electron shell of an atom; gaining, losing, or sharing electrons in this shell leads to bonding.

Giant Structure

An element or compound in which atoms or ions are linked by strong bonds in a continuous three-dimensional lattice.

Giant Covalent Structure

A giant lattice in which every atom is joined to others by multiple covalent bonds, as in diamond or graphite.

Metallic Bond

The strong attraction between positive metal ions and the sea of delocalised electrons within a metal lattice.

Simple Structure (Simple Molecular)

A substance composed of discrete molecules held together by weak intermolecular forces, e.g., H₂O, CO₂.

Intermolecular Forces

Weak attractive forces between molecules that are overcome during melting or boiling of simple molecular substances.

Melting Point

The temperature at which a solid becomes a liquid; high for giant structures, low for simple molecular substances.

Boiling Point

The temperature at which a liquid becomes a gas; also high for giant structures and low for simple molecular substances.

Electrical Conductivity (Metals)

The ability of metals to conduct electricity owing to the movement of delocalised electrons in their giant metallic structure.

Hydrogen Molecule (H₂)

A diatomic molecule formed when two hydrogen atoms share a pair of electrons via a single covalent bond.

Sodium Chloride (NaCl)

An ionic compound consisting of a giant lattice of Na⁺ and Cl⁻ ions held together by ionic bonds.

Weakness of Dot-and-Cross Model

Shows electron positions clearly but is two-dimensional, static, and fails to convey bond angles or relative sizes.