Past Papers — Gauteng 2023 Memo

Properties of materials:

• Strength
• Thermal and electrical conductivity
• Brittle, malleable, and ductile
• Magnetic or non-magnetic
• Density
• Melting points and boiling points

Classification of substances:

• What products are made of: atoms or molecules
• Elements or compounds
• Pure substances (element or compound) vs mixtures
• Mixtures: homogeneous or heterogeneous

Names of formulae and substances:

• Learn cation and anion tables
• Includes polyatomic ions (e.g. sulfate SO₄²⁻, nitrite NO₂⁻, hydroxide OH⁻, phosphate PO₄³⁻)
• Common household/traditional names (e.g. H₂O: water, HCl: hydrochloric acid, NH₃: ammonia, CO₂: carbon dioxide, H₂SO₄: sulfuric acid)
• Understanding scientific language for naming compounds (e.g. oxide)

Classification of metals, metalloids, and non-metals:

• Learn the properties of each
• Metalloids (semi-metals): understand their applications

States of matter:

• Verify particle nature by investigating diffusion and Brownian motion
• Characteristics of the three phases of matter
• Define freezing, melting, and boiling points
• Identify state of a substance given temperature, melting, and boiling points
• Define melting, evaporation, freezing, sublimation, condensation

Kinetic molecular theory:

• Describe solid, liquid, and gas in terms of kinetic molecular theory
• Describe phase changes using kinetic molecular theory
• Brownian motion and diffusion
• Heating and cooling curves
• Recognize phase changes on heating and cooling curves
• Understand that temperature does not change during phase changes

Atomic models:

• Know major contributions by Rutherford, Bohr, etc.
• Purpose of the atomic structure model

Atomic mass and structure:

• Atom is mainly empty space, nucleus is small
• Know structure: protons, neutrons, electrons
• Use periodic table to find atomic number, number of protons, electrons
• Understand ions: removing electrons changes neutrality, determine charge
• Calculate number of neutrons
• Calculate mass number of isotopes

Isotopes and relative atomic mass:

• Calculate relative atomic mass from isotope percentage abundances

Electron configuration:

• Draw orbital box diagrams
• Use spectroscopic electron configuration notation (Aufbau principle)
• Describe atomic orbitals, shape of s and p orbitals
• State Hund's rule and Pauli's exclusion principle

Position of elements and electronic arrangements:

• Table arranged by ascending atomic number
• Define group number and period number
• Relate position to electronic structure
• Understand periodicity of density, melting/boiling points, atomic radius
• Influence of periodicity on electron affinity and electronegativity
• Define atomic radius, ionization energy, electron affinity, electronegativity

Trends in the periodic table:

• Know trends: atomic radius, ionization energy changes up/down, left/right

Groups and reactivity:

• Relate electronic arrangements to properties of Groups 1, 2, 17, 18
• Describe differences in reactivity of Groups 1, 2, 17
• Predict properties of these groups

Location of different elements:

• Indicate location of metals, non-metals, and transition metals

Covalent Bonding:

• Draw Lewis dot diagrams of elements
• Sharing of electrons forms covalent bonds (single, double, triple)
• Electron diagrams of simple covalent bonds
• Names and formulae of covalent compounds
• Between non-metals, form molecules or giant network structures (e.g. diamond, graphite)

Ionic Bonding:

• Transfer of electrons forms ionic bonds (cations, anions)
• Electron diagrams of simple ionic compounds
• Ionic structure: crystal lattice

Metallic Bonding:

• Sharing of delocalized electron cloud among positive nuclei