Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for

several elements; for those that are nonmetals, only atomic radii are indicated.

Element Atomic Radius

$($nm$)$ Crystal Structure Electronegativity Valence

Cu $0\mathrm{.}1278$ FCC $1\mathrm{.}9+2$

C $0\mathrm{.}071$

H $0\mathrm{.}046$

O $0\mathrm{.}060$

Ag $0\mathrm{.}1445$ FCC $1\mathrm{.}9+1$

Al $0\mathrm{.}1431$ FCC $1\mathrm{.}5+3$

Co $0\mathrm{.}1253$ HCP $1\mathrm{.}8+2$

Cr $0\mathrm{.}1249$ BCC $1\mathrm{.}6+3$

Fe $0\mathrm{.}1241$ BCC $1\mathrm{.}8+2$

Ni $0\mathrm{.}1246$ FCC $1\mathrm{.}8+2$

Pd $0\mathrm{.}1376$ FCC $2\mathrm{.}2+2$

Pt $0\mathrm{.}1387$ FCC $2\mathrm{.}2+2$

Zn $0\mathrm{.}1332$ HCP $1\mathrm{.}6+2$

Which of these elements would you expect to form the following with copper:

$($a$)$ A substitutional solid solution having complete solubility

$($b$)$ A substitutional solid solution of incomplete solubility

$($c$)$ An interstitial solid solution