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What this unit covers

• Key concepts in chemistry: Give reasons why atoms contain equal numbers of protons and electrons.
• Key concepts in chemistry: Give a clear account of the way the Dalton model of an atom has changed over time because of the discovery of subatomic particles.
• Key concepts in chemistry: Give a clear account of the structure of an atom as a nucleus containing protons and neutrons, surrounded by electrons in shells.
• Key concepts in chemistry: Recall accurately the relative charge and relative mass of: a a proton b a neutron c an electron.
• Key concepts in chemistry: Give a clear account of the nucleus of an atom as very small compared to the overall size of the atom.
• Key concepts in chemistry: Recall accurately that most of the mass of an atom is concentrated in the nucleus.
• Key concepts in chemistry: Recall accurately the meaning of the term mass quantity of an atom.
• Key concepts in chemistry: Give a clear account of atoms of a given element as having an identical quantity of protons in the nucleus and that this number is unique to that element.
• Key concepts in chemistry: Give a clear account of isotopes as distinct atoms of an identical element containing an identical quantity of protons but distinct numbers of neutrons in their nuclei.
• Key concepts in chemistry: Work out the numbers of protons, neutrons and electrons in atoms given the atomic number and mass number.
• Key concepts in chemistry: Build an explanation of the way the existence of isotopes results in relative atomic masses of some elements not being whole numbers.
• Key concepts in chemistry: Work out the relative atomic mass of an element from the relative masses and abundances of its isotopes.
• Key concepts in chemistry: Give a clear account of the way Dmitri Mendeleev arranged the elements, known at that time, in a periodic table by using properties of these elements and their compounds.
• Key concepts in chemistry: Give a clear account of the way Dmitri Mendeleev used his table to predict the existence and properties of some elements not then discovered.
• Key concepts in chemistry: Explain that Dmitri Mendeleev thought he had arranged elements in order of increasing relative atomic mass but this was not always true because of the relative abundance of isotopes of some pairs of elements in the periodic table.
• Key concepts in chemistry: Build an explanation of the meaning of atomic quantity of an element by referring to position in the periodic table and quantity of protons in the nucleus.
• Key concepts in chemistry: Give a clear account of that in the periodic table a elements are arranged in order of increasing atomic number, in rows called periods b elements with similar properties are placed in an identical vertical columns called groups.
• Key concepts in chemistry: Recognise elements as metals or non-metals according to their position in the periodic table, explaining this division by referring to the atomic structures of the elements.
• Key concepts in chemistry: Make a justified prediction about the electronic configurations of the first 20 elements in the periodic table as diagrams and in the form, for example 2.8.1.
• Key concepts in chemistry: Build an explanation of the way the electronic configuration of an element is related to its position in the periodic table.
• Key concepts in chemistry: Build an explanation of the way ionic bonds are formed by the transfer of electrons between atoms to produce cations and anions, covering the use of dot and cross diagrams.
• Key concepts in chemistry: Recall accurately that an ion is an atom or group of atoms with a positive or negative charge.
• Key concepts in chemistry: Work out the numbers of protons, neutrons and electrons in simple ions given the atomic number and mass number.
• Key concepts in chemistry: Build an explanation of the formation of ions in ionic compounds from their atoms, limited to compounds of elements in groups 1, 2, 6 and 7.
• Key concepts in chemistry: Build an explanation of the use of the endings –ide and –ate in the names of compounds.
• Key concepts in chemistry: Deduce the formulae of ionic compounds (covering oxides, hydroxides, halides, nitrates, carbonates and sulfates) given the formulae of the constituent ions.
• Key concepts in chemistry: Build an explanation of the structure of an ionic compound as a lattice structure a consisting of a regular arrangement of ions b held together by strong electrostatic forces (ionic bonds) between oppositely-charged ions.
• Key concepts in chemistry: Build an explanation of the way a covalent bond is formed when a pair of electrons is shared between two atoms.
• Key concepts in chemistry: Recall accurately that covalent bonding results in the formation of molecules.
• Key concepts in chemistry: Recall accurately the typical size (order of magnitude) of atoms and small molecules.
• Key concepts in chemistry: Build an explanation of the formation of simple molecular, covalent substances, using dot and cross diagrams, covering: a hydrogen b hydrogen chloride c water d methane e oxygen f carbon dioxide.
• Key concepts in chemistry: Give reasons why elements and compounds may be classified as: a ionic b simple molecular (covalent) c giant covalent d metallic and how the structure and bonding of these types of substances results in distinct physical properties, covering relative melting point and boiling point, relative solubility in water and ability to conduct electricity (as solids and in solution).
• Key concepts in chemistry: Build an explanation of the properties of ionic compounds limited to: a high melting points and boiling points, by referring to forces between ions b whether or not they conduct electricity as solids, when molten and in aqueous solution.
• Key concepts in chemistry: Build an explanation of the properties of typical covalent, simple molecular compounds limited to: a low melting points and boiling points, by referring to forces between molecules (intermolecular forces) b poor conduction of electricity.
• Key concepts in chemistry: Recall accurately that graphite and diamond are distinct forms of carbon and that they are examples of giant covalent substances.
• Key concepts in chemistry: Give a clear account of the structures of graphite and diamond.
• Key concepts in chemistry: Explain, by referring to structure and bonding, why graphite is used to make electrodes and as a lubricant, whereas diamond is used in cutting tools.
• Key concepts in chemistry: Build an explanation of the properties of fullerenes covering C and graphene 60 by referring to their structures and bonding.
• Key concepts in chemistry: Give a clear account of, using poly(ethene) as the example, that simple polymers consist of large molecules containing chains of carbon atoms.
• Key concepts in chemistry: Build an explanation of the properties of metals, covering malleability and the ability to conduct electricity.
• Key concepts in chemistry: Give a clear account of the limitations of particular representations and models, to include dot and cross, ball and stick models and two- and three-dimensional representations.
• Key concepts in chemistry: Give a clear account of most metals as shiny solids which have high melting points, high density and are good conductors of electricity whereas most non-metals have low boiling points and are poor conductors of electricity.
• Key concepts in chemistry: Work out: a relative formula mass given relative atomic masses b percentage by mass of an element in a compound given relative atomic masses.
• Key concepts in chemistry: Work out the formulae of simple compounds from reacting masses or percentage composition and understand that these are empirical formulae.
• Key concepts in chemistry: Deduce: a the empirical formula of a compound from the formula of its molecule b the molecular formula of a compound from its empirical formula and its relative molecular mass.
• Key concepts in chemistry: Give a clear account of an experiment to determine the empirical formula of a simple compound for example magnesium oxide.
• Key concepts in chemistry: Build an explanation of the law of conservation of mass applied to: a a closed system covering a precipitation reaction in a closed flask b a non-enclosed system covering a reaction in an open flask that takes in or gives out a gas.
• Key concepts in chemistry: Work out masses of reactants and products from balanced equations, given the mass of one substance.
• Key concepts in chemistry: Work out the concentration of solutions in g dm –3.
• Key concepts in chemistry: Work out the quantity of: a moles of particles of a substance in a given mass of that substance and vice versa b particles of a substance in a given quantity of moles of that substance and vice versa c particles of a substance in a given mass of that substance and vice versa.
• Key concepts in chemistry: Give reasons why, in a reaction, the mass of product formed is controlled by the mass of the reactant which is not in excess.
• Key concepts in chemistry: Deduce the stoichiometry of a reaction from the masses of the reactants and products.