The spatial arrangement of atoms is central to the understanding of structure and properties. Hands-on manipulation of physical models is fundamental to understanding the three-dimensional atomic nature of materials, even with the availability of increasingly sophisticated computer displays. During the workshop we will make use of four different physical model kits based on hub and spoke (especially useful for covalent bonding), sphere packing (especially useful for ionic structures), polyhedral coordination (especially useful for oxides and environmental chemistry), and magnetic attraction (especially useful for showing the energetics of bond formation and addressing the common misconception among students that all bond formation requires energy.) Is a tetrahedron four spokes from a central atom, the space between four close-packed spheres, or a structural unit used to assemble larger structures? Multiple representations provide complementary views. We will also use some online models that allow switching between representations.
