Chemical Giants

Work done in this Nuffield 13 - 16 module followed from the S unit called Metals. This X unit provided enough material for eight double periods. It could be selected to complete either a Science or a Further Science course. The teachers’ guide included 13 worksheets to supplement the students’ booklet.

This module was designed to deal with the relationship between the structure of materials and their properties. Chapters one and two developed the idea of metals being giant structures of atoms, their crystalline nature being explained in terms of Bragg's bubble raft model. The malleable nature of metals and the alloying effect were explained, using this model. Chapter three dealt with the nonmetallic element, carbon. The differing properties of diamond and graphite were explained in terms of the different arrangements of atoms. Chapter four described the elements chlorine and iodine. Their uses were presented visually and no attempt was made to explain these in terms of chemical properties.

Chapter five pulled the ideas on structure together; the relationship between structural type (giant or molecular) and melting-point and boiling-point were examined for elements and extended to compounds. Chapters six, seven, and eight introduced the students to some very simple polymer chemistry. Again, the accent was on explaining the properties in terms of structure.

Contents
1. Finding evidence for metal giants
2. Model making
3. A non-metallic giant - carbon
4. Some molecular midgets - iodine and chlorine
5. Sorting the giants from the midgets
6. Giant molecules from molecular midgets
7. Looking at the properties of polymers
8. Elastomers