Chapter 2 - Atoms, Molecules, and Ions - Questions and Exercises - Exercises - Page 87: 2.96

(a) rhodium (II) bromide (b) copper (I) cyanide (c) vanadium (III) nitrate

(a) rhodium (II) bromide Rhodium (Rh) is a transition metal that has more than one valence. Let us look at the anion to see if we can determine which valence we have for iron. Bromine (Br) has a valence of 1-. We need two atoms of bromine for every atom of rhodium; therefore, we know that rhodium has a valence of 2+. To specify that the valence of this particular atom of rhodium is 2+, we place the Roman numeral II in parentheses next to the name of the cation, rhodium. We then add the name of the anion (bromine), changing its ending to $-ide$. (b) copper (I) cyanide Copper (Cu) is a transition metal that has more than one valence. Let us look at the anion to see if we can determine which valence we have for copper. We look to Table 2.2 on page 65 of our book to see that cyanide (CN$^{-}$) has a valence of 1-. Copper and cyanide are present in a 1:1 ratio in this compound; therefore, we know that copper has a valence of 1+. To specify that the valence of this particular atom of copper is 1+, we place the Roman numeral I in parentheses next to the name of the cation, copper. We then add the name of the anion (cyanide) as-is. (c) vanadium (III) nitrate Vanadium (V) is a transition metal that has more than one valence. Let us look at the anion to see if we can determine which valence we have for vanadium. We look to Table 2.2 on page 65 of our book to see that nitrate (NO$_3$$^{-}$) has a valence of 1-. We need three nitrate ions for every vanadium atom; therefore, we know that vanadium has a valence of 3+. To specify that the valence of this particular atom of vanadium is 3+, we place the Roman numeral III in parentheses next to the name of the cation, vanadium. We then add the name of the anion (nitrate) as-is.