QuestionQuestionConceptConceptDocumentDocument

Structure 1. Models of the particulate nature of matter

Start with Concept to understand a topic, then use Question Bank to check what you know.

5 topics · 23 learning objectives

Your progress

Sign in to see your mastery and mistakes.

  1. 1.1 Introduction to the particulate nature of matter

    1. • Elements: primary constituents of matter, cannot be chemically broken down • Compounds: atoms of different elements bonded in fixed ratio • Mixtures: more than one element/compound in no fixed ratio, separated by physical methods • Distinguish homogeneous and heterogeneous mixtures and choose separation methods

    2. • Explains physical properties of matter (solids, liquids, gases) and changes of state • State symbols: s, l, g, aq • Name changes of state: melting, freezing, vaporization, condensation, sublimation, deposition

    3. • Temperature T (Kelvin) = measure of average kinetic energy Ek • Convert between Celsius and Kelvin scales • Interpret temperature and physical property changes during changes of state

  2. 1.2 The nuclear atom

    1. • Nucleus: protons + neutrons (nucleons), positively charged, dense • Electrons: negatively charged, occupy space outside nucleus • Use nuclear symbols to deduce protons, neutrons, and electrons in atoms and ions

    2. • Same element, different numbers of neutrons • Nuclear symbol: Z^A X (Z = protons, A = mass number) • Calculate relative atomic masses from isotopic abundance • Understand isotope physical property differences; specific isotope examples are not required

    3. • Determine relative atomic masses from isotopic composition • Interpret mass spectra for isotope identity and abundance • Operational details of the mass spectrometer are not assessed

  3. 1.3 Electron configurations

    1. 1.3.1Emission spectra

      • Produced when electrons in excited states return to lower energy levels • Relationship: colour, wavelength, frequency, energy across electromagnetic spectrum • Continuous vs. line spectrum

    2. 1.3.2Hydrogen emission spectrum

      • Evidence for discrete energy levels • Energy transitions to n=1, n=2, n=3 • Describe convergence at higher energies; series names are not assessed

    3. 1.3.3Main energy levels

      • Integer n, holds maximum 2n² electrons • Deduce maximum electrons in each main energy level

    4. 1.3.4Sublevels

      • Main energy levels divided into s, p, d, f sublevels • Shapes: s orbital (spherical), three p orbitals (dumbbell) • Link sublevels to s, p, d, f blocks in the periodic table

    5. 1.3.5Orbitals and electron spin

      • Each orbital holds 2 electrons of opposite spin • Aufbau principle, Hund's rule, Pauli exclusion principle • Electron configurations for atoms and ions up to Z=36 • Use full, condensed, and orbital box diagrams; include Cr and Cu exceptions

    6. 1.3.6(HL)—Ionization energy (IE)

      • Convergence limit = ionization • Trends in 1st IE across period and down group • Calculate 1st IE from spectral data (wavelength/frequency)

    7. 1.3.7(HL)—Successive ionization energies

      • Provide information about electron configuration • Deduce element's group from successive IE data

  4. 1.4 The mole

    1. • SI unit of amount of substance • One mole = Avogadro constant number of entities • Convert between amount of substance and number of specified particles

    2. • Compared to ¹²C standard • Determine relative formula mass from relative atomic masses

    3. • Units: g mol⁻¹ • Relationships: particles ↔ moles ↔ mass • Solve mass, mole, and particle problems using n = m/M

    4. • Empirical: simplest ratio of atoms • Molecular: actual number of atoms in molecule • Interconvert percentage composition and empirical formula • Determine molecular formula from empirical formula and molar mass

    5. • Determined by amount of solute and volume of solution • Solve concentration, amount, and volume problems; square brackets mean molar concentration

    6. • Equal volumes of gases (same T, P) contain equal numbers of molecules • Mole ratio calculations with gas volumes • Use gas volume ratios from balanced equations

  5. 1.5 Ideal gases

    1. • Moving particles, negligible volume, no intermolecular forces • Elastic collisions

    2. • Deviate from ideal at low temperature and high pressure

    3. • Constant at specific T and P • Analyse temperature, pressure, and volume graphs for a fixed mass of gas

    4. • PV = nRT • Combined gas law: P₁V₁/T₁ = P₂V₂/T₂ • Solve ideal gas problems with correct pressure, volume, and temperature units