Section 1: Principles of Chemistry Specification

a) States of matter

1.1 understand the arrangement, movement and energy of the particles in each
of the three states of matter: solid, liquid and gas

1.2 understand how the interconversions of solids, liquids and gases are
achieved and recall the names used for these interconversions

1.3 explain the changes in arrangement, movement and energy of particles
during these interconversions.

b) Atoms

1.4 describe and explain experiments to investigate the small size of particles
and their movement including:
i dilution of coloured solutions
ii diffusion experiments

1.5 understand the terms atom and molecule

1.6 understand the differences between elements, compounds and mixtures

1.7 describe experimental techniques for the separation of mixtures, including
simple distillation, fractional distillation, filtration, crystallisation and paper
chromatography

1.8 explain how information from chromatograms can be used to identify the
composition of a mixture.

c) Atomic structure

1.9 understand that atoms consist of a central nucleus, composed of protons
and neutrons, surrounded by electrons, orbiting in shells

1.10 recall the relative mass and relative charge of a proton, neutron and electron
1.11 understand the terms atomic number, mass number, isotopes and relative
atomic mass (Ar)

1.12 calculate the relative atomic mass of an element from the relative
abundances of its isotopes

1.13 understand that the Periodic Table is an arrangement of elements in order of
atomic number

1.14 deduce the electronic configurations of the first 20 elements from their
positions in the Periodic Table

1.15 deduce the number of outer electrons in a main group element from its
position in the Periodic Table.

d) Relative formula masses and molar volumes of gases

1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar)

1.17 understand the use of the term mole to represent the amount of substance

1.18 understand the term mole as the Avogadro number of particles
(atoms, molecules, formulae, ions or electrons) in a substance

1.19 carry out mole calculations using relative atomic mass (Ar) and relative
formula mass (Mr)

1.20 understand the term molar volume of a gas and use its values
(24 dm3 and 24,000 cm3) at room temperature and pressure (rtp) in
calculations.

e) Chemical formulae and chemical equations

1.21 write word equations and balanced chemical equations to represent the
reactions studied in this specification

1.22 use the state symbols (s), (l), (g) and (aq) in chemical equations to
represent solids, liquids, gases and aqueous solutions respectively

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

1.24 calculate empirical and molecular formulae from experimental data

1.25 calculate reacting masses using experimental data and chemical equations

1.26 calculate percentage yield

1.27 carry out mole calculations using volumes and molar concentrations.

f) Ionic compounds

1.28 describe the formation of ions by the gain or loss of electrons

1.29 understand oxidation as the loss of electrons and reduction as the gain of
electrons

1.30 recall the charges of common ions in this specification

1.31 deduce the charge of an ion from the electronic configuration of the atom
from which the ion is formed

1.32 explain, using dot and cross diagrams, the formation of ionic compounds by
electron transfer, limited to combinations of elements from Groups 1, 2, 3
and 5, 6, 7

1.33 understand ionic bonding as a strong electrostatic attraction between
oppositely charged ions

1.34 understand that ionic compounds have high melting and boiling points
because of strong electrostatic forces between oppositely charged ions

1.35 understand the relationship between ionic charge and the melting
point and boiling point of an ionic compound

1.36 describe an ionic crystal as a giant three-dimensional lattice
structure held together by the attraction between oppositely
charged ions

1.37 draw a diagram to represent the positions of the ions in a crystal of
sodium chloride.

g) Covalent substances

1.38 describe the formation of a covalent bond by the sharing of a pair of
electrons between two atoms

1.39 understand covalent bonding as a strong attraction between the bonding
pair of electrons and the nuclei of the atoms involved in the bond

1.40 explain, using dot and cross diagrams, the formation of covalent compounds
by electron sharing for the following substances:
i hydrogen
ii chlorine
iii hydrogen chloride
iv water
v methane
vi ammonia
vii oxygen
viii nitrogen
ix carbon dioxide
x ethane
xi ethene

1.41 understand that substances with simple molecular structures are gases or
liquids, or solids with low melting points

1.42 explain why substances with simple molecular structures have low melting
and boiling points in terms of the relatively weak forces between the
molecules

1.43 explain the high melting and boiling points of substances with giant covalent
structures in terms of the breaking of many strong covalent bonds

1.44 draw diagrams representing the positions of the atoms in diamond
and graphite

1.45 explain how the uses of diamond and graphite depend on their
structures, limited to graphite as a lubricant and diamond in cutting.

h) Metallic crystals

1.46 understand that a metal can be described as a giant structure of positive
ions surrounded by a sea of delocalised electrons

1.47 explain the electrical conductivity and malleability of a metal in terms of its
structure and bonding.

i) Electrolysis

1.48 understand that an electric current is a flow of electrons or ions

1.49 understand why covalent compounds do not conduct electricity

1.50 understand why ionic compounds conduct electricity only when molten or in
solution

1.51 describe experiments to distinguish between electrolytes and nonelectrolytes

1.52 understand that electrolysis involves the formation of new substances when
ionic compounds conduct electricity

1.53 describe experiments to investigate electrolysis, using inert electrodes, of
molten salts such as lead(II) bromide and predict the products

1.54 describe experiments to investigate electrolysis, using inert
electrodes, of aqueous solutions such as sodium chloride, copper(II)
sulfate and dilute sulfuric acid and predict the products

1.55 write ionic half-equations representing the reactions at the electrodes during
electrolysis

1.56 recall that one faraday represents one mole of electrons

1.57 calculate the amounts of the products of the electrolysis of molten
salts and aqueous solutions.