Student Exploration Covalent Bonds Answer Key: Fill & Download for Free

There is not a single correct answer to this question because every subtopic that mineralogy touches can be covered in ever-expanding detail. Complementing these topics with practical exercises depends on the equipment and the technical support that is available in any one institution, and the expertise of the instructor.The crystalline nature of minerals is an obvious starting point, but there is considerable variation in the detail in which crystal forms, their Miller indices, and the differences in degrees of symmetry between classes or at the atomic-level (how to translate a space group to a point group) could be covered and explored in practical exercises. It remains important to know enough about crystal systems, their systems of axes and how Miller indices relate to them to be able to read diagrams of crystal drawings and how they relate to their main optical properties. Some mineralogy courses introduce the optical properties of minerals seen under the petrographic microscopes, but others may stress techniques like X-ray powder diffraction and Raman spectroscopy. One should cover at least the basics of electron microprobe analysis and the recalculation of a mineral formula from a list of oxides.Some mineral identification is typically involved in mineralogy courses, and it must necessarily be selective. Should the students see only 30 important minerals, or be exposed to a much wider range? This depends a lot on the quality of the teaching material available. There is no hard and fast rule other than covering enough diversity to introduce examples of the main physical properties useful for mineral identification, and relating some to the key aspects of the chemical bonding character and symmetry of crystal structures. Examples from the subclasses of silicates are a natural starting point for that reason. Some mineralogy courses integrate aspects of petrology by contrasting the aspect of the same minerals in the main rock types that are typical of continental and oceanic crust, but a mineralogy course may also choose to emphasize ore minerals (the source of the most widely used elements in everyday life or technology) and industrial minerals.Asking students to think of a chemical formula as proportions of elements in a 3D pattern rather than as a single molecule is quite a leap for some students who cling to images of molecules and the octet rule seen in their general chemistry course.Pauling’s rules are stressed in mineralogy textbooks, yet their practical application is rather limited in an introductory course. Encouraging students to think of chemical bonding as a spectrum rather than categories (dominantly ionic but with some covalent character, and mixed covalent/metallic character) is important, as are the role of weaker interactions (van der Waals forces in graphite and sulfur, hydrogen bonding in gypsum).Variability of chemical composition as solid solution, and phase diagrams (binary and ternary systems) that describe limited solid solution (olivine, feldspars, pyroxenes, rhombohedral carbonates), and crystallization and cooling paths that lead to unmiscibility and exsolution.