Chemistry Chapters 2 and 3 Review: Chemical Bonding, Nomenclature, and Intermolecular Forces

Vocabulary practice flashcards covering core chemical bonding concepts, IUPAC nomenclature rules for ionic and molecular compounds, electronegativity trends, molecular polarity, and intermolecular forces from Chapters 2 and 3.

Chemical Bond

The force of attraction that holds two atoms or ions together in a compound.

Ionic Bond

The electrostatic force of attraction between a positive ion (cation) and a negative ion (anion), typically formed by the transfer of electrons from a metal atom to a non-metal atom ($\Delta EN \ge 1.7$).

Electrolyte

A substance that dissolves in water to form a solution that conducts electricity by releasing free-floating, mobile ions.

Crystal Lattice Structure

The rigid, highly ordered, repeating three-dimensional arrangement of positive and negative ions held together in a fixed ratio within an ionic solid.

Formula Unit

The smallest repeating unit in an ionic crystal structure that represents the lowest whole-number ratio of cations to anions.

Zero-Sum Rule

The chemical convention stating that the total positive charge of all cations in an ionic compound must equal the total negative charge of all anions, producing an electrically neutral chemical formula.

Multivalent Metal

A metal atom capable of forming a variety of cations with different charges (such as $Fe^{2+}$ and $Fe^{3+}$), which are distinguished in nomenclature using Roman numerals.

Binary Ionic Compound

An ionic compound composed of only two different elements: a metallic cation and a non-metallic anion (e.g., $NaCl$, $MgCl_2$).

Polyatomic Ion

A single unit of two or more covalently bonded atoms that carries an overall electric charge shared across the entire ion.

Oxyanion

A negatively charged polyatomic ion consisting of oxygen bonded to another non-metallic element (e.g., $CO_3^{2-}$, $NO_3^-$, $SO_4^{2-}$).

Parent Oxyanion

The most common and stable oxyanion combination of a non-metal with oxygen, designated by the non-metal stem followed by the suffix '-ate' (e.g., chlorate, $ClO_3^-$).

Per-…-ate Rule

The IUPAC oxyanion naming rule where the prefix 'per-' and suffix '-ate' are used when an oxyanion has one more oxygen atom than the parent '-ate' ion (e.g., perchlorate, $ClO_4^-$).

-ite Rule

The IUPAC oxyanion naming rule where the suffix '-ite' replaces '-ate' when an oxyanion has one fewer oxygen atom than the parent '-ate' ion (e.g., chlorite, $ClO_2^-$).

Hypo-…-ite Rule

The IUPAC oxyanion naming rule where the prefix 'hypo-' and suffix '-ite' are added when an oxyanion has two fewer oxygen atoms than the parent '-ate' ion (e.g., hypochlorite, $ClO^-$).

Hydrate

An ionic compound that contains a specific number of water molecules bound within its crystal structure in a fixed ratio (e.g., calcium chloride dihydrate, $CaCl_2 \cdot 2H_2O$).

Covalent Bond

A chemical bond formed when two non-metal atoms share one or more pairs of valence electrons to achieve stable electron configurations.

Bonding Capacity

The maximum number of covalent bonds an individual atom can form with other atoms, typically corresponding to the number of unpaired valence electrons in its outer shell.

Lone Pair

A pair of unshared valence electrons located in the outer energy level of an atom that is not involved in chemical bonding.

Structural Formula

A visual representation of a molecular compound that shows the arrangement of atoms and chemical bonds using lines for shared pairs, while typically omitting lone pairs.

Electronegativity

The relative ability of an individual bonded atom to attract bonding electron pairs toward itself, developed on a scale by Linus Pauling in 1922 ranging from francium ($0.7$) to fluorine ($4.0$).

Non-Polar Covalent Bond

A covalent bond formed between two identical or nearly identical non-metal atoms that share bonding electrons equally ($\Delta EN = 0$).

Polar Covalent Bond

A covalent bond formed between atoms with an intermediate electronegativity difference ($0 < \Delta EN < 1.7$) where electrons are shared unequally, creating partial negative ($\delta^-$) and partial positive ($\delta^+$) charges.

Polar Molecule

A molecule that possesses an asymmetric distribution of charge or asymmetrical geometry, resulting in permanently separated positive ($\delta^+$) and negative ($\delta^-$) dipole poles (e.g., $H_2O$, $HCl$).

Non-Polar Molecule

A molecule that contains only non-polar covalent bonds, or possesses a symmetrical shape whose individual polar bond dipoles cancel out completely (e.g., $O_2$, $CO_2$).

Intermolecular Forces

Relatively weak forces of electrostatic attraction that occur between separate molecules, dictating physical properties such as melting point, boiling point, state of matter, and surface tension.

Van der Waals Forces

The collective scientific term used to describe the weak intermolecular forces consisting of London dispersion forces and dipole-dipole forces.

London Dispersion Forces (LDF)

The weakest intermolecular forces present in all atoms and molecules, caused by momentary, temporary shifts in electron positions creating fleeting instantaneous and induced dipoles.

Dipole-Dipole Forces

Intermediate-strength intermolecular forces that occur exclusively between polar molecules due to the electrostatic attraction between the permanent $\delta^+$ end of one molecule and the $\delta^-$ end of an adjacent molecule.

Hydrogen Bond

The strongest intermolecular force, occurring when a highly electropositive hydrogen atom bonded covalently to nitrogen ($N$), oxygen ($O$), or fluorine ($F$) is attracted to a lone pair on an electronegative atom of a neighbouring molecule.

Hexagonal Crystalline Lattice of Ice

The open, hydrogen-bonded molecular arrangement that forms as liquid water freezes and expands, causing solid ice to have a lower density than liquid water and float.

Specific Heat Capacity of Water

A property of water characterized by a high resistance to temperature change per unit of thermal energy absorbed, due to the substantial amount of heat required to disrupt hydrogen bonds between molecules.

Surface Tension

The inward pulling force at the surface of a liquid caused by intermolecular attractions; in water, it is primarily produced by strong hydrogen bonding between adjacent water molecules.

Renewable Resource

A natural material or substance that replenishes itself through natural processes as quickly as it is consumed (e.g., water, wood, sugarcane, corn).

Non-Renewable Resource

A natural resource that exists in finite supply and cannot be replaced or regenerated as quickly as it is consumed (e.g., crude oil, aluminum ore, fossil fuels).

Petrochemical

A chemical substance or molecular compound manufactured or derived directly from non-renewable fossil fuels, such as petroleum or natural gas.