S2.4 From Model to Materials

• Bonding is best described as a continuum between the ionic, covalent and metallic models, and can be represented by a bonding triangle.

• The position of a compound in the bonding triangle is determined by the relative contributions of the three bonding types to the overall bond. 

• Alloys are mixtures of a metal and other metals or non-metals. They have enhanced properties.

• Polymers are large molecules, or macromolecules, made from repeating subunits called monomers.

• Addition polymers form by the breaking of a double bond in each monomer.

• (AHL) Condensation polymers form by the reaction between functional groups in each monomer with the release of a small molecule.

Structure 3.1—How do the trends in properties of period 3 oxides reflect the trend in their bonding?

Nature of science, Structures 2.1, 2.2—What are the limitations of discrete bonding categories?

Structure 2.1, 2.2, 2.3—Why do composites like reinforced concretes, which are made from ionic and covalently bonded components and steel bars, have unique properties?

Structure 1.1—Why are alloys more correctly described as mixtures rather than as compounds?

Structure 3.2—What are the structural features of some plastics that make them biodegradable?

Structure 3.2—What functional groups in molecules can enable them to act as monomers for addition reactions?

Reactivity 2.1—Why is the atom economy 100% for an addition polymerization reaction?

(AHL) Structure 3.2—What functional groups in molecules can enable them to act as monomers for condensation reactions?