Could anyone explain how one might determine the packing structure of a particular material (i.e. FCC, BCC)? The question is asked several times in the Clio Invitational test that was posted a while back and there are no explanations given.
Unfortunately, that one is something that you sort of have to just know. There isn't really a way to determine it as far as I know from just the name, it is mostly an intuitive sense. You should study crystal structures of common materials as well as the most typical crystal structure for each class of materials in order to have the best idea as to the crystal structure of a given material. In my experience, FCC is the most common structure for a wide range of materials. However, it does vary even for the same material. Iron, for example, can exist as BCC (delta, beta, and alpha iron), FCC (gamma iron), and HCP (Epsilon iron)
Can you explain what exactly the prefixes s- and p- on number 15 mean? My partner and I couldn't figure out what exactly you meant by it. Our first guess was sigma and pi bonds, but that would mean the answer would be s-sp3. Our second guess was it had to do with the p orbitals of the CL atoms. Could you clarify what exactly the prefix of the answer means (we understand the sp3 part).