Unit 1 Matter and Bonding Radiation Alpha: A heavy, positively charged particle made of 2 protons and 2 neutrons; it can be stopped by paper or skin. Beta: A fast-moving, negatively or positively charged particle (electron or
positron); it can pass through skin but is stopped by materials like aluminum. Gamma and X-ray: A high-energy electromagnetic wave with no mass or charge; it can penetrate most materials and requires lead or concrete to block.
Alkaline metal: Group 1 (vertical). soft, shiny, very reactive, and form +1 ions. Alkaline earth metal: Group 2. reactive, form +2 ions, but less reactive than alkali metals. Atom: The smallest unit of an element, consisting of a
nucleus containing protons and neutrons, surrounded by electrons. Atomic mass: The average mass of all the atoms of an element, taking into account the relative abundance of its isotopes. Atomic number: The number of protons
in the nucleus of an atom, which determines the element’s identity. Atomic radius: A measure of the size of an atom, typically the distance from the nucleus to the outermost electron shell. Compound: A pure substance formed
when two or more elements are chemically bonded in fixed ratios. Electron: A negatively charged subatomic particle that orbits the nucleus of an atom. Electron affinity: The energy change that occurs when an atom gains an
electron; it reflects an atom’s ability to attract electrons. Electronegativity: The tendency of an atom to attract shared electrons in a chemical bond. Element: A substance made of only one kind of atom, identified by its atomic
number. Energy level: A specific region around the nucleus where electrons can exist; also called an electron shell. Flame test: A laboratory technique used to identify metal ions based on the color they emit when heated in a
flame. Halogen: Elements in Group 17. They are reactive nonmetals. Ion: An atom or molecule that has gained or lost electrons, positive (cation) or negative (anion). Ionization energy: The amount of energy required to remove an
electron from a neutral atom in the gas phase. Isotope: same element, different numbers of neutrons, different masses. Line spectrum: A pattern of specific wavelengths of light emitted by excited atoms, unique to each element.
Metal: An element that is a good conductor of heat and electricity, is malleable, ductile, and typically has a shiny appearance. Metalloid: An element with properties that are intermediate between those of metals and nonmetals, red
lines right. Neutron: A neutral subatomic particle found in the nucleus of an atom. Noble gas: Elements in Group 18. They are stable and nonreactive due to having full outer electron shells. Nonmetal: red letters. An element that
does not conduct heat or electricity well and tends to gain electrons during reactions. Nucleus: The dense central core of an atom, composed of protons and neutrons. Period: A horizontal row on the periodic table; elements in the
same period have the same number of energy levels. Periodic trend: A recurring pattern in the properties of elements across a period or down a group, such as atomic radius or electronegativity. Proton: A positively charged
subatomic particle found in the nucleus of an atom. Transition metal: Elements in Groups 3–12 (the d-block) that often have variable charges and can form colored compounds. Trend: A general pattern observed among elements
on the periodic table, such as increasing ionization energy across a period. Valence electrons: The electrons in the outermost energy level of an atom, which determine how the atom bonds with others. Binary compound: A
compound made up of exactly two different elements, such as sodium chloride (NaCl). Bonding capacity: The number of electrons an atom uses to form chemical bonds in order to achieve a full valence shell. Chemical bond: The
attractive force that holds atoms together in compounds, including ionic, covalent, and metallic bonds. Coordinate covalent bond: A type of covalent bond in which both shared electrons come from the same atom. Covalent bond:
A chemical bond formed when two atoms share one or more pairs of electrons. Diatomic molecule: H2, N2, O2, Cl2, F2, Br2, I2. A molecule consisting of two atoms, which may be of the same or different elements. Dipole–
dipole force: between polar molecules, Stronger than London, (Special one: hydrogen bonding, stronger than regular, occurs when H is bonded to N, O, or F), the intermolecular attraction between the positive end of one polar
molecule and the negative end of another. Conductivity: The ability of a substance to allow electric current to pass through, often due to the presence of free ions or electrons. Electrolyte: A substance that dissolves in water to
produce a solution that conducts electricity by forming ions. Electron dot diagram: A visual representation showing valence electrons as dots around the symbol of an element; also called a Lewis dot diagram. Hydrogen bonding:
A strong type of dipole–dipole attraction that occurs when hydrogen is bonded to nitrogen, oxygen, or fluorine. Intramolecular force: The force that holds atoms together within a molecule, such as covalent or ionic bonds. Ionic
bond: a bond formed by the electrostatic attraction between positively and negatively charged ions. Ionic compound: A compound composed of cations and anions held together by ionic bonds in a crystal lattice. Lewis structure:
A diagram that shows the arrangement of valence electrons in a molecule, including bonding and lone pairs. London dispersion force: weakest, between all molecules, temporary intermolecular force caused by momentary uneven
electron distributions in all atoms and molecules. Lone pair: A pair of valence electrons that are not shared or bonded to another atom. Molecular compound: A compound formed from nonmetals sharing electrons through covalent
bonds to create individual molecules. Octet rule: The tendency of atoms to form bonds that result in eight electrons in their valence shell, similar to noble gases. Polar covalent bond: A covalent bond in which electrons are shared
unequally, resulting in partial charges on the atoms. Polar molecule: A molecule with an uneven distribution of charge, leading to a dipole moment. Polyatomic ion: A charged group of covalently bonded atoms that acts as a single
ion, such as OH- or NH4+. Stable octet: A full outer electron shell containing eight electrons, associated with chemical stability. Valence: Refers to the number of electrons an atom can use to bond with other atoms; related to
valence electrons or bonding capacity. Unit 2 Chemical Reactions Physical reaction: A change in state or form, such as melting or dissolving, where the chemical identity of the substance remains unchanged; Chemical reaction: A
process in which substances are transformed into new substances with different chemical and physical properties; Combustion: A chemical reaction in which a substance reacts with oxygen, releasing heat and usually light,
commonly forming carbon dioxide and water; Single displacement reaction: Occurs when one element replaces another in a compound; Double displacement reaction: Involves ions in two compounds switching places to form
new compounds, often resulting in a precipitate or neutralization; Addition reaction: A chemical reaction where two or more reactants combine to form a single product; Synthesis: A type of addition reaction in which simpler
substances combine to form a more complex compound; Decomposition: A chemical reaction where one compound breaks down into two or more simpler substances; Activity series: A list of elements ranked by reactivity, used to
predict whether a single displacement reaction will occur; Yield: The amount of product formed in a chemical reaction; Products: The new substances formed in a chemical reaction, written on the right side of the equation;
Reactants: The starting substances in a chemical reaction, written on the left side of the equation; Solute: The substance that dissolves in a solution; Solubility: The maximum amount of solute that can dissolve in a specific amount
of solvent at a given temperature; Solvent: The substance that dissolves the solute to form a solution, commonly water; Alloy: A homogeneous mixture of metals or of a metal with another element, such as steel or bronze;
Precipitate: A solid that forms and settles out from a liquid solution during a chemical reaction; Neutralization reaction: A chemical reaction between an acid and a base that produces water and a salt.Unit 3 Quantities in Reactions
Stoichiometry: The calculation of quantities of reactants and products using a balanced chemical equation; Percentage yield: Calculated by dividing the actual yield by the theoretical yield and multiplying by 100 to show reaction
efficiency; Limiting reagent: The reactant that is used up first, determining the maximum amount of product that can be formed; Excess reagent: The reactant that remains after the limiting reagent is completely used up; Mole: A
unit that represents 6.022 × 10²³ particles (atoms, molecules, ions); Atomic mass: The average mass of atoms of an element, weighted by the abundance of its isotopes; Empirical formula: Shows the simplest whole-number ratio of
elements in a compound; Molecular formula: Gives the actual number of atoms of each element in a molecule; Molar mass: The mass of one mole of a substance, measured in grams per mole (g/mol); Actual yield: The measured
amount of product actually obtained from a reaction; Gravimetric stoichiometry: Stoichiometry involving mass-to-mass calculations; Quantitative analysis: Involves measuring the quantities or concentrations of substances in a
sample; Theoretical yield: The maximum amount of product expected from a chemical reaction, based on stoichiometric calculations.Unit 4 Solutions Concentration: The amount of solute dissolved in a specific amount of
solution, commonly expressed in mol/L; Dilute: Describes a solution with a low concentration of solute; Dilution: The process of adding more solvent to decrease the concentration of a solution; Dissociation: The process where an
ionic compound breaks apart into its ions when dissolved in water; Electrolyte: A substance that conducts electricity in solution due to the presence of free-moving ions; Homogeneous mixture: A mixture in which the composition
is uniform throughout, such as a solution; Intermolecular force: A force of attraction between molecules Intramolecular force: A force holding atoms together within a molecule, such as a covalent bond; Molar concentration: The
number of moles of solute per litre of solution; Mole: Also used here to calculate concentrations (molarity = mol/L); Solution: A homogeneous mixture made up of a solute dissolved in a solvent; Standard solution: A solution with
a precisely known concentration; Stock solution: A highly concentrated solution used to prepare lower-concentration solutions by dilution. Net ionic equation: Includes only the species directly involved in the chemical reaction,
leaving out spectator ions; Precipitate: Repeated here because it is often the result shown in ionic equations; Spectator ion: An ion that exists in the same form on both sides of a chemical equation and does not participate in the
reaction; Solubility: Critical for determining whether a precipitate will form (repeated for importance); Solution stoichiometry: Involves stoichiometric calculations with substances in solution, usually using molarity; Qualitative
data: Refers to observable properties such as color, texture, or phase change; Quantitative data: Refers to measurable quantities like mass, volume, or concentration; Total ionic equation: Shows all dissolved ionic compounds as
separated ions in the reaction. Acid: A substance that donates a hydrogen ion (H⁺) in solution; Base: A substance that accepts a hydrogen ion or donates hydroxide ions (OH⁻) in solution; Conjugate acid: The species formed when
a base gains a proton (H⁺); Conjugate base: The species formed when an acid loses a proton; Conjugate acid–base pair: Consists of two species that differ by the presence of one hydrogen ion; Dissociation: Also applies here, as
acids and bases dissociate into ions in solution; Endpoint: The point in a titration where the indicator changes color, signaling that the reaction is complete; Hydronium ion (H₃O⁺): Formed when a hydrogen ion bonds with a
water molecule in acidic solutions; Ionization: The process in which a molecule forms ions in solution; Neutralization: A reaction between an acid and a base that produces water and a salt; Percentage ionization: Measures the
fraction of acid molecules that ionize in solution, expressed as a percentage; pH: A measure of the acidity or basicity of a solution, calculated as the negative logarithm of the hydronium ion concentration; Titrant: The solution of
known concentration added during titration; Titration: A laboratory technique used to determine the unknown concentration of a solution through a controlled reaction with a titrant. Unit 5 Gases Gas properties: Compressibility:
Gases can be compressed because their particles are far apart and have space to move closer. Expansion: Gases expand to fill the shape and volume of their container. Low Density: Gas particles are spread out, so gases generally
have much lower density than solids or liquids. Diffusion: Gas particles spread out and mix with other gases due to their random motion. Effusion: The process where gas particles pass through tiny holes without collisions.
Pressure: Gas particles collide with container walls, creating pressure. Volume: The space gas particles occupy; it changes with temperature and pressure. Temperature: Reflects the average kinetic energy (speed) of gas particles.
Ideal gass:1. No intermolecular forces 2. Elastic collisions 3. Negligible particle volume 4. Random, constant motion Real gases approximate ideal behavior under: High temperature, Low pressure