Question

determine the chemical formula of the ionic compounds listed below: 1. magnesium nitride 2. calcium oxide 3. potassium iodide 4. lithium chloride 5. potassium sulfide

Explanation:

Step1: Recall ion - charges

Magnesium forms a $Mg^{2 + }$ ion and nitrogen forms an $N^{3 - }$ ion. To balance the charges, we need 3 magnesium ions and 2 nitrogen ions.

Step2: Write the formula

The chemical formula of magnesium nitride is $Mg_3N_2$.

Step3: Recall ion - charges for calcium oxide

Calcium forms a $Ca^{2+}$ ion and oxygen forms an $O^{2 - }$ ion. The ratio of calcium to oxygen is 1:1.

Step4: Write the formula

The chemical formula of calcium oxide is $CaO$.

Step5: Recall ion - charges for potassium iodide

Potassium forms a $K^{+}$ ion and iodine forms an $I^{-}$ ion. The ratio of potassium to iodine is 1:1.

Step6: Write the formula

The chemical formula of potassium iodide is $KI$.

Step7: Recall ion - charges for lithium chloride

Lithium forms a $Li^{+}$ ion and chlorine forms a $Cl^{-}$ ion. The ratio of lithium to chlorine is 1:1.

Step8: Write the formula

The chemical formula of lithium chloride is $LiCl$.

Step9: Recall ion - charges for potassium sulfide

Potassium forms a $K^{+}$ ion and sulfur forms an $S^{2 - }$ ion. To balance the charges, we need 2 potassium ions and 1 sulfur ion.

Step10: Write the formula

The chemical formula of potassium sulfide is $K_2S$.

Answer:

1. $Mg_3N_2$
2. $CaO$
3. $KI$
4. $LiCl$
5. $K_2S$