Chapter 3 - Compounds

Vocabulary flashcards covering periodic trends, chemical bonding types, ionic and covalent compound properties, nomenclature, and Lewis structures from Chapter 3.

Atomic Radius

Half the distance between the nuclei of identical atoms that are chemically bonded together, influenced by electron configuration, nuclear charge, and valence energy level.

Electronegativity ($\chi$)

A measure of the attraction an element has for the electrons in a chemical bond.

Chemical Bond

A stabilizing link between atoms formed when a balance between attractive and repulsive forces is reached as atoms collide.

Ionic Bond

A chemical bond formed between a metal and a nonmetal with a large electronegativity difference ($\Delta\chi$), resulting in valence electrons being transferred from the metal to the nonmetal.

Covalent Bond

A chemical bond formed between nonmetal atoms with a small electronegativity difference ($\Delta\chi$), resulting in valence electrons being shared between atoms.

Metallic Bond

A chemical bond between metal atoms characterized by delocalized electron sharing, where valence electrons float freely throughout the metal atoms.

"Sea of Electrons" Model

A model of metallic bonding where valence electrons are shared among multiple atoms and float freely, accounting for properties such as malleability, ductility, electrical and thermal conductivity, hardness, and strength.

Cation

A positively charged ion formed when a metal atom loses valence electrons (e.g., $Na^{+1}$).

Anion

A negatively charged ion formed when a nonmetal atom gains valence electrons (e.g., $Cl^{-1}$).

Octet Rule

The tendency for atoms to gain, lose, or share electrons in order to acquire the stable electron configuration of a full valence shell (usually $8$ electrons, except for $H$ and $He$ which require $2$).

Diatomic Molecule

A two-atom covalent compound (such as $H_2$) with perfect electron sharing between the bonded atoms.

Hydride Ion

A negatively charged ion ($H^{-1}$) formed when hydrogen acts like a halogen by gaining one electron when bonded with low-electronegativity elements.

Formula Unit

The representative unit of an ionic compound, which is electrically neutral overall and represents the simplest ratio of cations to anions.

Molecule

The representative unit of a covalent compound, which is electrically neutral and does not contain ions.

Electrolyte

A chemical compound that dissociates into ions when dissolved in water ($aq$) and is therefore capable of transporting an electric charge.

Binary Compound

A compound that contains only two different elements (e.g., binary ionic $NaCl$ or binary covalent $H_2O$).

Polyatomic Ion

An ion made of more than one atom covalently bonded together that carries an overall positive or negative charge (e.g., $NH_4^+$, $OH^-$, $NO_3^-$, $PO_4^{3-}$, $SO_4^{2-}$).

Chemical Nomenclature

A systematic step-by-step process used to name chemical compounds.

Chemical Formula

A representation showing the simplest ratio of elements that make up a unique compound.

Single Covalent Bond

A covalent bond formed when $1$ pair of valence electrons is shared between two atoms.

Double Bond

A covalent bond formed when $2$ pairs of valence electrons are shared between two atoms.

Triple Bond

A covalent bond formed when $3$ pairs of valence electrons are shared between two atoms.

Expanded Octet

An exception to the octet rule occurring in nonmetals larger than neon (in the $3\text{rd}$ energy level or higher) that can accommodate more than $8$ valence electrons in available d-orbitals when acting as the central atom (e.g., $SF_6$).

Nonpolar Covalent Bond

A covalent bond formed between identical nonmetal atoms or between carbon and hydrogen, characterized by very low $\Delta\chi$ and even sharing of electrons.

Polar Covalent Bond

A covalent bond formed between different nonmetal elements (excluding C and H) with a higher $\Delta\chi$, causing electrons to be shared unevenly and resulting in a slightly positive end ($\delta+$) and a slightly negative end ($\delta-$).

Lewis Structure

A structural representation using element symbols and dots to show the valence electrons of single atoms and the arrangement of electrons in a compound.

Electron Dot Diagram

The Lewis structure of a single atom, created by writing the element symbol and placing dots around it one side at a time to represent each valence electron.