Earth Materials Midterm Exam Review Outline Spring 2006Review session 8:30 pm Wednesday night room 219 (lecture room) – bring specific questions, problems (ex. “Can you explain Pauling’s rules?” is not a specific question, “How can I determine if a molecular subunit is anisodesmic, mesodesmic, or isodesmic?”)All Materials may be found in either the notes or the material covered in the book (and usually both).The following is an outline of the material which you are expected to be responsible for on the mid-term exam next week (pertinent sections in text bracketed)1. General chemistry of Earth Materials (Chapter 1):a. Distribution of elements in the universe and on earth b. Types of bonds – an understanding in particular of ionic and covalent bondingin common minerals as well as other types of bonds2. Pauling’s Rules (Chapter 13)a. Should know first 2 inside and out (radius ratio and electrostatic valency principle) to determine coordination numbers, bond strengthb. Know difference between isodesmic, anisodesmic, and mesodesmic subunits, as well as describe how they are important in bonding and silica polymerization3. Know the 7 ways in which silica tetrahedral polymerize, forming the major divisions of silicate minerals (Chapter 13 page 287-290)4. Mineral formulas (Chapter 1, page 21-22)a. Be able to read chemical formulasb. use binary and ternary compositional diagrams c. Be able to normalize a simple chemical formula5. Know what a polymorph is, be able to discuss why they form6. Mineral Growth – be able to discuss different ways minerals form and get bigger… (Chapter 2)7. Be able to discuss different kinds of defects, dislocations, imperfections (like twinning, zoning) (Chapter 2)8. Be able to discuss chemical fingerprints – chemical makeup, isotopes9. Symmetry elements – know the different operators and have some understanding that they combine to define point groups (Chapter 9)10. Know the 6 major crystal systems very well!! (Chapter 10)11. Know how crystal morphology (form) is related to a crystal’s internal structure12. Miller indices (Chapter 11, page 242-247)13. Crystallography – be able to define a lattice, unit cell (Chapter 10)a. Know differences between the 14 Bravais lattices (unit cell types – primitive, body, face, end-centered)b. Know how space groups are defined symmetry point groups, Bravais lattices, translations14. Light absorption – you should have a good working knowledge of the electromagnetic spectrum and basic properties (especially wave forms), wave-particleduality. (Chapter 4)a. Color – be well-versed in different ways in which color is developed in minerals – be able to bring together mineral chemistry/ structure with light interaction!b. Luster, diaphaneity – be able to define in terms of light interactionc. You should have a general understanding of luminescence (difference betweenfluorescence and phospholuminescence)15. Mineral physical properties – have a working knowledge of hardness, density, magnetism (know types!) and acid reaction how does all of it relate to mineral chemistry/ structure (Chapter 3)16. interaction of electrons ‘shot’ at a mineral know how electrons may interact and reflect as well as transmit through minerals and what some of the information this canprovide using SEM, TEM and related detectors17. Spectroscopic methods – use your understanding of the interaction of light with minerals to describe the different analytical methods to analyze minerals. For instance, if I was interested in how to distinguish different clays by investigating the prescence of OH groups, what tool(s) could I use? IR spectroscopy, which looks atthe vibration of the O-H bond.18. X-rays – Be able to describe how X-rays are generated and ways they interact with minerals (Chapter 12)19. Interference – you should understand constructive and destructive interference as applied to any form of electromagnetic radiation!20. Diffraction – be able to describe diffraction, relationship to spacing of atoms in planes(defined through crystallography) (Chapter 12)21. Bragg’s Law – you should understand this very well, be able to use it to generate an XRD pattern, describe how it works with different sources of radiation, and what kindof information we can get from X-ray diffraction experiments utilizing Bragg’s Law (Chapter 12)22. Optical microscopy (Chapter 4, better description in lab book)a. How polarizers work in a petrographic microscopeb. Be able to describe how color, relief, pleochroism develop in plane polarized lightc. Be able to describe light reorientation by minerals under cross polarsd. Recognize how internal order affects optical properties how are the 6 majorcrystal classes divided in terms of optical properties, how can you use optical microscopy to tell between certain classes?e. Be able to describe basic principles of refraction, ordinary vs. extraordinary rays, and how this relates to extinction and birefringencef. Describe basics of conoscopic projections in microscopy (Bertrand lense), differences between isometric, uniaxial, biaxial
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