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C2 Elements, compounds and mixtures

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do non-metals share electrons to form covalent bonds, and what structures can result?

Covalent bonding as shared pairs of electrons between non-metals, dot and cross diagrams for simple molecules, simple molecular substances, and giant covalent structures such as diamond, graphite and silicon dioxide.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.1 on covalent bonding, covering shared pairs of electrons, dot and cross diagrams for simple molecules, the properties of simple molecular substances, and giant covalent structures including diamond, graphite and silicon dioxide.
9 min answer →

How do metals and non-metals transfer electrons to form ionic bonds, and what holds an ionic compound together?

Ionic bonding as the transfer of electrons between metals and non-metals, the formation of positive and negative ions, dot and cross diagrams, ionic formulae, and the giant ionic lattice.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.1 on ionic bonding, covering electron transfer between metals and non-metals, the formation of ions, dot and cross diagrams, working out ionic formulae, and the giant ionic lattice structure.
9 min answer →

What is metallic bonding, and how does it explain the properties of metals and alloys?

Metallic bonding as a lattice of positive ions in a sea of delocalised electrons, the link to the properties of metals (conduction, malleability, high melting points), and why alloys are harder than pure metals.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.1 on metallic bonding, covering the lattice of positive ions in a sea of delocalised electrons, how this explains electrical and thermal conduction, malleability and high melting points, and why alloys are harder than pure metals.
8 min answer →

What are nanoparticles, why does size matter so much, and how do we represent the states of substances?

Nanoparticles, coarse and fine particles, the high surface area to volume ratio of nanoparticles and its consequences, uses and risks of nanoparticles, and the state symbols used in equations.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.2 on nanoparticles, covering the sizes of coarse, fine and nanoparticles, the surface area to volume ratio and why it matters, the uses and risks of nanoparticles, and the state symbols used in chemical equations.
8 min answer →

What is the difference between a pure substance and a mixture, and how can mixtures be separated?

Pure substances, mixtures and formulations, and the techniques for separating mixtures: filtration, crystallisation, simple and fractional distillation, and paper chromatography with Rf values.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.3 on pure substances, mixtures and formulations, and the separation techniques of filtration, crystallisation, simple and fractional distillation and paper chromatography including Rf value calculations.
9 min answer →

How are the bonding and structure of a substance related to its properties?

Relating bonding and structure to the properties of substances: melting and boiling points, electrical conductivity and state, across ionic, simple molecular, giant covalent and metallic substances, and the limitations of bonding models.
A focused answer to OCR Gateway GCSE Chemistry A topic C2.2 on how bonding and structure determine properties, comparing the melting points, conductivity and state of ionic, simple molecular, giant covalent and metallic substances, and noting the limitations of the bonding models.
9 min answer →