Ol 4.4 Below, atomic radius, crystal structure, elec- tronegativity, and the most common valence are tabulated, for several elements: for those that are nonmetals, only atomic radii are indicated. Element Crystal Electro- Structure negativity FCC 1.8 Valence +2 Ni H 0 Ag Atomic Radius (nm) 0.1246 0.071 0.046 0.060 0.1445 0.1431 0.1253 0.1249 0.1241 0.1387 0.1332 Cr Fe Pt FCC FCC HCP BCC FCC HCP 1.9 1.5 1.8 1.6 1.8 2.2 1.6 +3 +2 +3 +2 +2 Which of these elements would you expect to form the following with nickel: (a) A substitutional solid solution having complete solubility (b) A substitutional solid solution of incom- plete solubility (e) An interstitial solid solution