1 Principles of chemistry

Understand the three states of matter in terms of the arrangement, movement and energy of the particles

Understand the interconversions between the three states of matter in terms of:

• the names of the interconversions
• how they are achieved
• the changes in arrangement, movement and energy of the particles.

Understand how the results of experiments involving the dilution of coloured solutions and diffusion of gases can be explained

Know what is meant by the terms:

• solvent
• solute
• solution
• saturated solution.

Know what is meant by the term solubility in the units g per 100 g of solvent

Understand how to plot and interpret solubility curves

Practical: investigate the solubility of a solid in water at a specific temperature

Understand how to classify a substance as an element, compound or mixture

Understand that a pure substance has a fixed melting and boiling point, but that a mixture may melt or boil over a range of temperatures

Describe these experimental techniques for the separation of mixtures:

• simple distillation
• fractional distillation
• filtration
• crystallisation
• paper chromatography.

Understand how a chromatogram provides information about the composition of a mixture

Understand how to use the calculation of Rf values to identify the components of a mixture

Practical: investigate paper chromatography using inks/food colourings

Know what is meant by the terms atom and molecule

Know the structure of an atom in terms of the positions, relative masses and relative charges of sub-atomic particles

Know what is meant by the terms atomic number, mass number, isotopes and relative atomic mass (Ar)

Be able to calculate the relative atomic mass of an element (Ar) from isotopic abundances

Understand how elements are arranged in the Periodic Table:

• in order of atomic number
• in groups and periods.

Understand how to deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table

Understand how to use electrical conductivity and the acid-base character of oxides to classify elements as metals or non-metals

Identify an element as a metal or a non-metal according to its position in the Periodic Table

Understand how the electronic configuration of a main group element is related to its position in the Periodic Table

Understand why elements in the same group of the Periodic Table have similar chemical properties

Understand why the noble gases (Group 0) do not readily react

Write word equations and balanced chemical equations (including state symbols):

• for reactions studied in this specification
• for unfamiliar reactions where suitable information is provided.

Calculate relative formula masses (including relative molecular masses) (Mr) from relative atomic masses (Ar)

Know that the mole (mol) is the unit for the amount of a substance

Understand how to carry out calculations involving amount of substance, relative atomic mass (Ar) and relative formula mass (Mr)

Calculate reacting masses using experimental data and chemical equations

Calculate percentage yield

Understand how the formulae of simple compounds can be obtained experimentally, including metal oxides, water and salts containing water of crystallisation

Know what is meant by the terms empirical formula and molecular formula

Calculate empirical and molecular formulae from experimental data

Carry out calculations involving amount of substance, solution volume and concentration in mol/dm³.

Carry out gas-volume calculations using a molar gas volume of 24 dm³ mol⁻¹ (24 000 cm³ mol⁻¹) at room temperature and pressure.

Practical: know how to determine the formula of a metal oxide by combustion (e.g. magnesium oxide) or by reduction (e.g. copper(II) oxide)

Understand how ions are formed by electron loss or gain

Know the charges of Group 1, 2, 3, 5, 6 and 7 ions and Ag⁺, Cu²⁺, Fe²⁺, Fe³⁺, Pb²⁺, Zn²⁺, H⁺, OH⁻, NH₄⁺, CO₃²⁻, NO₃⁻ and SO₄²⁻.

Write formulae for compounds formed between the ions listed above

Draw dot-and-cross diagrams to show the formation of ionic compounds by electron transfer, limited to combinations of elements from Groups 1, 2, 3 and 5, 6, 7 only outer electrons need be shown

Understand ionic bonding in terms of electrostatic attractions

Understand why compounds with giant ionic lattices have high melting and boiling points

Know that ionic compounds do not conduct electricity when solid, but do conduct electricity when molten and in aqueous solution

Know that a covalent bond is formed between atoms by the sharing of a pair of electrons

Understand covalent bonds in terms of electrostatic attractions

Understand how to use dot-and-cross diagrams to represent covalent bonds in:

• diatomic molecules, including hydrogen, oxygen, nitrogen, halogens and hydrogen halides
• inorganic molecules including water, ammonia and carbon dioxide
• organic molecules containing up to two carbon atoms, including methane, ethane, ethene and those containing halogen atoms.

Explain why simple molecular substances are gases, liquids or low-melting solids in terms of intermolecular forces of attraction.

Explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass

Explain why substances with giant covalent structures are solids with high melting and boiling points

Explain how the structures of diamond, graphite and C60 fullerene influence their physical properties, including electrical conductivity and hardness

Know that covalent compounds do not usually conduct electricity

Know how to represent a metallic lattice by a 2-D diagram

Understand metallic bonding in terms of electrostatic attractions

Explain typical physical properties of metals, including electrical conductivity and malleability

Understand why covalent compounds do not conduct electricity

Understand why ionic compounds conduct electricity only when molten or in aqueous solution

Know that anion and cation are terms used to refer to negative and positive ions respectively

Describe experiments to investigate electrolysis, using inert electrodes, of molten compounds (including lead(II) bromide) and aqueous solutions (including sodium chloride, dilute sulfuric acid and copper(II) sulfate) and to predict the products

Write ionic half-equations representing the reactions at the electrodes during electrolysis and understand why these reactions are classified as oxidation or reduction

Practical: investigate the electrolysis of aqueous solutions