High School chemistry

A substance that donates protons (H+ ions) in a reaction (Brønsted-Lowry definition) or accepts a pair of electrons (Lewis definition). Acids typically have a pH less than 7.

Different structural forms of the same element in the same physical state. Examples include diamond and graphite, both made of carbon atoms.

An anion is a negatively charged ion formed when an atom gains electrons. A cation is a positively charged ion formed when an atom loses electrons.

A solution in which water acts as the solvent. Many chemical reactions important in biology and industry occur in aqueous solutions.

The fundamental building block of matter, consisting of a nucleus (protons and neutrons) surrounded by electrons. It is the smallest unit of an element that retains the chemical identity of that element.

The number of protons found in the nucleus of an atom. It uniquely identifies an element and is denoted by the symbol Z.

The number of constituent particles (atoms, molecules, ions, etc.) in one mole of a substance, approximately 6.022 x 10^23 particles/mol. It links macroscopic mass to microscopic particles.

The process of ensuring that the number of atoms of each element is the same on both the reactant and product sides of a chemical equation. This adheres to the Law of Conservation of Mass.

A substance that accepts protons (H+ ions) in a reaction (Brønsted-Lowry definition) or donates a pair of electrons (Lewis definition). Bases typically have a pH greater than 7.

An attractive force that holds atoms together in molecules or compounds. It results from the sharing or transfer of valence electrons between atoms.

A state in a reversible chemical reaction where the rate of the forward reaction equals the rate of the reverse reaction. At equilibrium, the concentrations of reactants and products remain constant.

A process that involves the rearrangement of the atomic structure of substances, resulting in the formation of new substances with different properties. It involves breaking and forming chemical bonds.

Properties of solutions that depend only on the number of solute particles dissolved in a given amount of solvent, not on the identity of the solute particles. Examples include boiling point elevation and freezing point depression.

A pure substance formed when two or more different elements are chemically bonded together in fixed proportions. Compounds have properties distinct from their constituent elements.

A measure of the amount of solute present in a given amount of solution or solvent. It can be expressed in various units, such as molarity (moles/liter).

A type of chemical bond formed when two atoms share one or more pairs of electrons. This usually occurs between two nonmetal atoms to achieve a stable electron configuration.

A separation of electric charge within a molecule, resulting in a positive end and a negative end. This occurs due to unequal sharing of electrons in covalent bonds.

The distribution of electrons of an atom or molecule in atomic or molecular orbitals. It describes the arrangement of electrons in shells and subshells.

A measure of an atom's ability to attract electrons in a chemical bond. It generally increases across a period and decreases down a group.

A pure substance consisting of only one type of atom, which cannot be broken down into simpler substances by chemical means. Each element is defined by its unique number of protons.

The empirical formula shows the simplest whole-number ratio of atoms in a compound. The molecular formula shows the actual number of atoms of each element in a molecule.

The capacity to do work or produce heat. In chemistry, it's involved in breaking and forming bonds, driving reactions, and influencing the stability of substances.

The ground state is the lowest energy state of an atom where electrons occupy the lowest available orbitals. An excited state occurs when an electron absorbs energy and moves to a higher energy orbital.

A strong type of intermolecular force that occurs when hydrogen is bonded to a highly electronegative atom (like N, O, or F) and is attracted to another electronegative atom in a different molecule.

Attractive forces that exist between molecules, influencing physical properties like boiling points and solubility. They are weaker than intramolecular (covalent or ionic) bonds.

An atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge (positive for cations, negative for anions).

A type of chemical bond formed between a metal and a nonmetal through the complete transfer of one or more electrons. This creates oppositely charged ions that attract each other.

The minimum energy required to remove one mole of electrons from one mole of gaseous atoms in their ground state to form one mole of gaseous ions. It indicates how tightly an atom holds its electrons.

Atoms of the same element that have the same number of protons but different numbers of neutrons. This results in different mass numbers for the same element.

Atoms of the same element that have the same number of protons but different numbers of neutrons. This leads to variations in their atomic mass.

The reactant in a chemical reaction that is completely consumed first, thereby determining the maximum amount of product that can be formed. It limits the extent of the reaction.

The reactant in a chemical reaction that is completely consumed first, thereby determining the maximum amount of product that can be formed. It limits the reaction's extent.

The total number of protons and neutrons in the nucleus of an atom. It represents the approximate mass of the atom in atomic mass units (amu).

A type of chemical bond found in metals, characterized by a "sea" of delocalized valence electrons shared among a lattice of positively charged metal ions. This gives metals their unique properties.

The mass of one mole of a substance, expressed in grams per mole (g/mol). It is numerically equal to the atomic or molecular weight in atomic mass units (amu).

The SI unit for amount of substance, defined as the number of particles (atoms, molecules, ions) equal to Avogadro's number (6.022 x 10^23). It links macroscopic mass to microscopic particles.

The smallest unit of a pure substance that can exist independently and retain the chemical properties of that substance. It consists of two or more atoms held together by chemical bonds.

The loss of electrons by an atom, molecule, or ion during a chemical reaction. It typically results in an increase in the oxidation state of the species.

The ratio of the actual yield (the amount of product experimentally obtained) to the theoretical yield (the maximum amount of product calculated from stoichiometry), expressed as a percentage.

A tabular arrangement of chemical elements, organized by their atomic number, electron configuration, and recurring chemical properties. It allows for the prediction of element characteristics.

A logarithmic scale used to specify the acidity or basicity of an aqueous solution. It ranges from 0 to 14, where 7 is neutral, values below 7 are acidic, and values above 7 are basic.

An ion composed of two or more atoms covalently bonded together that collectively carry a net electrical charge. Examples include sulfate (SO4^2-) and ammonium (NH4+).

The new substances formed as a result of a chemical reaction. They are typically written on the right side of a chemical equation.

The starting materials in a chemical reaction that undergo transformation. They are typically written on the left side of a chemical equation.

The gain of electrons by an atom, molecule, or ion during a chemical reaction. It typically results in a decrease in the oxidation state of the species.

The substance that is dissolved in a solvent to form a solution. It is typically present in a smaller amount than the solvent.

A homogeneous mixture composed of two or more substances, where one substance (solute) is uniformly dispersed in another (solvent). The components cannot be easily separated.

The substance in a solution that dissolves the other substance (solute). It is typically present in the larger amount and determines the physical state of the solution.

The distinct forms that matter can take: solid, liquid, gas, and plasma. These states are primarily determined by temperature and pressure, which affect the arrangement and energy of particles.

The branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions. It uses balanced chemical equations to predict amounts.

Electrons located in the outermost electron shell of an atom. They are primarily involved in chemical bonding and determine an element's reactivity.

Valence Shell Electron Pair Repulsion theory predicts the three-dimensional geometry of molecules based on the repulsion between electron pairs in the valence shell of the central atom.