## Chemistry (7th Edition)

(a) $MgF_2$ (b) $SnO_2$ (c) $Fe_2S_3$
(a) Magnesium is represented by $Mg$, and fluoride is made of fluorine $F$. $MgF$ As we can see in figure 2.15 (Page 61), $Mg$ has a charge of $2+$, so we multiply the number of fluorides by 2. $MgF_2$ (b) Tin is represented by $Sn$, and oxide ion is made of oxygen, $O$. $SnO$ As we can see in its name, tin IV has a charge of $4+$, so we multiply the number of oxygens by 4. As we can see in figure 2.15 (Page 61), $O$ has a charge of $2-$, so we multiply the number of tin by 2. $Sn_4O_2$ Simplifying it: $Sn_2O$ (c) Iron is represented by $Fe$, and sulfide ion is made of sulfur, $S$. $FeS$ As we can see in its name, iron (III) has a charge of $3+$, so we multiply the number of sulfides by 3. As we can see in figure 2.15 (Page 61), sulfide has a charge of $2-$, so we multiply the number of irons by 2. $Fe_2S_3$