AP Chemistry Review (Units 1-5)

Vocabulary flashcards covering atomic structure, bonding, intermolecular forces, chemistry laws, and kinetics based on lecture notes for Units 1 through 5.

Isotopes

Atoms of the same element that have different numbers of neutrons (e.g., $Cl-35$ and $Cl-37$).

Atomic mass unit (amu)

A unit of mass determined by the sum of the number of protons and neutrons in an atom.

Average Atomic mass

The weighted average of the masses of all naturally occurring isotopes of an element (e.g., $Cl$ is $35.45$).

1 mole

A unit of measurement equivalent to $6.02 \times 10^{23}$ particles or molecules.

Empirical formula

A chemical formula that shows the lowest whole number ratio of elements in a compound.

Electron configurations

A description of where electrons are located in an atom (e.g., for Chlorine: $1s^2 2s^2 2p^6 3s^2 3p^5$).

Orbital

A region in space where an electron spends $90\%$ of its time; its distance from the nucleus is defined by the energy level.

Atomic radius

The size of an atom measured from the center of the nucleus to the outer orbitals.

Ionization energy

The amount of energy required to remove an electron from an atom.

Ionic bonds

Bonds formed between a metal and a nonmetal where the nonmetal extracts electrons due to high electronegativity; these compounds are hard, brittle, and have high melting/boiling points.

Covalent bonds

Bonds formed between two nonmetals characterized by the sharing of electrons; these substances typically have low melting/boiling points.

Metallic bonds

Bonds between metal atoms described by the "sea of e-" model, making them malleable, ductile, and conductive.

Hybridization

The mixing of atomic orbitals (such as $s$ and $p$) to make molecular orbitals (such as $sp$, $sp^2$, or $sp^3$).

Resonance Structure

Occurs when there is more than one acceptable Lewis structure for a molecule (e.g., $SO_2$).

Formal charge

A value calculated as $\text{Valence electrons} - \text{dots} - \text{lines}$ to determine the best resonance structure; the goal is a charge of $0$.

Coulomb's Law

A principle stating that opposite charges attract and the force of attraction is stronger when the charges are close together.

Intermolecular Forces (IMF)

Forces of attraction that occur between particles.

Hydrogen Bond

A strong IMF where a Hydrogen atom is bonded to a highly electronegative atom ($F$, $O$, or $N$).

Dipole-dipole

A force of attraction between polar molecules.

London Dispersion Force (LDF)

An attraction between nonpolar molecules due to the random motion of electrons.

Polarizable

The tendency of an electron cloud to be distorted; a molecule with more electrons is more polarizable and has stronger LDFs.

Molarity ($M$)

A measure of concentration defined as $\frac{\text{moles solute}}{\text{liter solution}}$.

Solubility

The ability of a substance to dissolve into a solvent, often following the principle that "like dissolves like" (e.g., polar dissolves polar).

Beer's Law

A law stating that the absorbance of a solution is directly proportional to its concentration ($A = \epsilon bc$).

Precipitation Reaction

A chemical reaction in which a solid is produced from the reaction of aqueous solutions.

Redox Reactions

Chemical reactions where electrons are transferred, resulting in a change in oxidation numbers.

Activation energy

The minimum amount of energy required to initiate a chemical reaction.

Rate Law

An expression relating the concentration of reactants to the rate of the reaction (e.g., $R = k [A]^x [B]^y$).

Rate-determining step

The slowest step in a reaction mechanism that governs the overall speed of the chemical reaction.