The density of an unknown metal is 2.64 g/cm3 and its atomic radius is 0.215 nm. It has a face-centered cubic lattice. Determine its atomic weight.

6. A compound consists of A-atoms and B-atoms, and its solid crystal forms a cubic unit cell structure, as shown below. A-atoms occupy corners and faces of the cube. B-atoms are inside the cube and are not shared by adjacent cubic unit cells. Based on the information here, we can conclude that (a) A-atoms form an FCC structure; the empirical formula of the compound is A,B2. (b) A-atoms form an FCC structure; the empirical formula of the compound is AB. (c) A-atoms form a BCC structure; the empirical formula of the compound is A¬B2. (d) A-atoms form a BCC structure; the empirical formula of the compound is AB. (e) None of the above. A-atoms (corners and faces) B-atoms (inside, not shared) a m n T OF THE FL EMENTS

8. Intensity (relative) 40.0 50.0 60.0 70.0 Diffraction angle 20 80.0 Figure 3.25 shows the first four peaks of the x-ray diffraction pattern for copper, which has an FCC crystal structure; monochromatic x-radiation having a wavelength of 0.1542 nm was used. (a) Index (i.e., give h, k, and / indices for) each of these peaks. (b) Determine the interplanar spacing for each of the peaks. (c) For each peak, determine the atomic ra- dius for Cu and compare these with the value presented in Table 3.1. 90.0 Figure 3.25 Diffraction pattern for polycrystalline copper.

Metallic chromium has a body- centered cubic structure (all atoms at the lattice points) and a density of 3 7.20 g/cm³. Assume chromium atoms to be spheres. The spheres in a body- centered array оcсиру 68.0% of the total space. Find the atomic radius of chromium. The volume of a sphere is equal to 4Tr /3. Radius = %3|