Learning Objectives 

2.4.1​ & 2.4.2: The Bonding  Triangle: Use the Van Arkel–Ketelaar triangle to classify bonding types based on electronegativity values. Recognize that some substances, like AlCl₃ and metalloids, exhibit both ionic and covalent or metallic and covalent character.

2.4.3: Alloys: Define alloys as mixtures containing metals. Describe how alloying improves strength, corrosion resistance, and other properties. Identify examples like stainless steel, bronze, and brass.

2.4.4: Polymers: Define polymers as long chains of monomers. Distinguish between natural and synthetic polymers. Understand repeating units and give examples like starch, cellulose, polyethene, and polystyrene. Note the use of biodegradable polymers.

2.4.5: Addition Polymerization: Describe addition polymerization as the linking of monomers with double bonds into polymers without by-products. Use ethene as an example and represent repeating units accurately.

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Higher Level

2.4.6: Condensation Polymerization (HL): Explain condensation polymerization as a process where monomers join with elimination of small molecules. Understand esterification (different monomers) and peptide bond formation (same monomer). Define hydrolysis as the reverse process.