Valence Electrons: Electrons in the outermost shell of an atom that are involved in chemical bonding.
Periodic Table: A tabular arrangement of chemical elements based on their atomic number, electron configuration, and recurring chemical properties.
Isotopes: Atoms of the same element with different numbers of neutrons in their nuclei, thus differing in atomic mass.
Ions: Atoms or molecules that have gained or lost electrons, thus acquiring a net positive or negative electrical charge.
How to read the Periodic Table: The periodic table is organized into periods (horizontal rows) and groups (vertical columns). Elements within the same group have similar chemical properties, while those within the same period have the same number of electron shells.
Molecules & Compounds: A molecule is a group of atoms held together by chemical bonds. Compounds are substances composed of two or more different elements chemically bonded together.
Molecular Formula & Isomers: A molecular formula shows the types and numbers of atoms present in a molecule. Isomers are molecules with the same molecular formula but different structural arrangements or spatial orientations of atoms.
Lewis-Dot-Structures: Diagrams that represent the valence electrons of atoms in a molecule using dots around the atomic symbol.
Why atoms bond: Atoms bond to achieve a more stable electron configuration and lower potential energy.
Covalent Bonds: Bonds formed by sharing pairs of electrons between atoms.
Electronegativity: A measure of an atom's ability to attract shared electrons in a chemical bond.
Ionic Bonds & Salts: Ionic bonds are bonds formed by the transfer of electrons from one atom to another, resulting in the formation of positively and negatively charged ions. Salts are ionic compounds composed of positive and negative ions held together by electrostatic attraction.
Metallic Bonds: Bonds formed between metal atoms due to the sharing of delocalized electrons.
Polarity: Unequal sharing of electrons in a covalent bond, resulting in partial positive and negative charges on atoms.
Intermolecular Forces: Forces of attraction or repulsion between molecules.
Hydrogen Bonds: Weak electrostatic attractions between a hydrogen atom bonded to a highly electronegative atom and another electronegative atom.
Van der Waals Forces: Weak forces of attraction between atoms or molecules resulting from temporary dipoles induced by fluctuations in electron distribution.
Solubility: The ability of a substance (solute) to dissolve in a solvent to form a homogeneous mixture (solution).
Surfactants: Compounds that lower the surface tension between two substances, such as water and oil.
Forces ranked by Strength: Different types of chemical bonds and intermolecular forces ranked from strongest to weakest.
States of Matter: The physical forms that substances can exist in: solid, liquid, gas, and plasma.
Temperature & Entropy: Temperature is a measure of the average kinetic energy of particles in a substance. Entropy is a measure of the disorder or randomness of a system.
Melting Points: The temperature at which a solid substance changes to a liquid state.
Plasma & Emission Spectrum: Plasma is a state of matter where atoms are stripped of their electrons, resulting in a mixture of positively charged ions and free electrons. Emission spectrum is the range of wavelengths emitted by atoms or molecules when they transition from excited to ground states.
Mixtures: Substances composed of two or more different compounds or elements physically mixed together but not chemically bonded.
Types of Chemical Reactions: Various ways in which chemical substances can react with each other, including synthesis, decomposition, combustion, and replacement reactions.
Stoichiometry & Balancing Equations: Stoichiometry is the study of the quantitative relationships between reactants and products in chemical reactions. Balancing equations involves ensuring that the number of atoms of each element is the same on both sides of a chemical equation.
The Mole: A unit of measurement used in chemistry to express amounts of chemical substances.
Physical vs Chemical Change: Physical changes involve alterations in the state or appearance of matter without changing its chemical composition, whereas chemical changes involve the formation of new substances with different chemical properties.
Activation Energy & Catalysts: Activation energy is the minimum amount of energy required for a chemical reaction to occur. Catalysts are substances that increase the rate of a chemical reaction by lowering the activation energy.
Reaction Energy & Enthalpy: Reaction energy is the difference in energy between reactants and products in a chemical reaction. Enthalpy is the total heat content of a system at constant pressure.
Gibbs Free Energy: A thermodynamic quantity that measures the maximum amount of reversible work that can be performed by a system at constant temperature and pressure.
Chemical Equilibriums: A state in which the rates of the forward and reverse reactions in a chemical system are equal, resulting in no net change in the concentrations of reactants and products.
Acid-Base Chemistry: The study of acids and bases, their properties, reactions, and behavior in aqueous solutions.
Acidity, Basicity, pH & pOH: Acidity refers to the concentration of hydrogen ions in a solution. Basicity refers to the concentration of hydroxide ions in a solution. pH is a measure of the acidity or basicity of a solution. pOH is the negative logarithm of the hydroxide ion concentration.
Neutralisation Reactions: Reactions between acids and bases that result in the formation of water and a salt.
Redox Reactions: Reactions in which there is a transfer of electrons between reactants.
Oxidation Numbers: Numbers assigned to atoms in a chemical compound to indicate their hypothetical charge if all the bonding electrons were assigned to the more electronegative atom.
Quantum Chemistry: The branch of chemistry that applies quantum mechanics to understand chemical systems and processes.
