Foundations

A simple gas model relates pressure, amount, volume and temperature.

The mole is linked to a specified number of entities.

The proton count of an atomic nucleus identifies its chemical element.

Isotopes share a proton count but have different neutron counts.

Atomic-number order reveals recurring patterns in electron structure and chemical properties.

Bonding describes interactions that bind atoms into molecules or extended structures.

The mole counts specified entities using the exact Avogadro constant.

Balanced coefficients relate the amounts consumed and produced by a reaction.

A chemical equation must preserve each element's atom count and the total charge.

At equilibrium, opposing reactions continue without net composition change.

In the Brønsted description, an acid donates a proton and a base accepts it.

Gibbs-energy change distinguishes thermodynamic favourability from reaction speed.

Reaction rate measures change over time; a rate law describes its dependence under specified conditions.

A catalyst changes the reaction pathway and rate, while preserving the equilibrium constant for the same reaction.

Metabolism comprises the regulated chemical reactions of living systems.

Carbon moves through biological, oceanic, atmospheric and geological reservoirs.

Quantum labels specify orbitals and spin states.

A periodic crystal potential organizes energies by wavevector and band.

Band occupancy and doping control mobile carriers.

Other electrons modify the attraction experienced by an electron in an atom.

Orbital occupations connect atomic electronic structure with valence chemistry.

Localized orbital overlap and resonance are complementary chemical descriptions.

A molecular orbital description distributes electronic states across a molecule.

Dispersion, dipole interactions and hydrogen bonding influence molecular materials.

Ionic, metallic, molecular and network solids organize common bonding patterns.

Polymers are substances composed of macromolecules with recurring structural units.

Ligand donor atoms surround a central metal in a coordination sphere.

Activity expresses composition relative to a specified thermodynamic standard state.

pH is an activity-based quantity realized through measurement conventions.

An acid–base pair can resist limited changes in solution pH.