Question 3, (10 points) Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for several metals. Please apply for conditions for substitutional solid solution (Hume - Rothery rule) to answer questions. Element Atomic Crystal Electro- Valence Structure nega- Radius (nm) tivity Cu 0.1278 FCC 1.9 +2 Ag 0.1445 FCC 1.9 +1 Al 0.1431 FCC 1.5 +3 Co 0.1253 HCP 1.8 +2 Cr 0.1249 BCC 1.6 +3 Fe 0.1241 BCC 1.8 +2 Ni 0.1246 FCC 1.8 +2 Pd 0.1376 FCC 2.2 +2 Zn 0.1332 HCP 1.6 +2 (a) Which metal is most likely to form a substitutional solid solution with Cu? Answer: (b) Please explain your idea. (8 points)