Question

directions: write the formulas of the following ionic compounds: 1. potassium iodide 2. magnesium oxide 3. aluminum chloride 4. beryllium phosphide 5. calcium chloride

Explanation:

Step1: Determine the ions

• Potassium ion (\(K^+\)), iodide ion (\(I^-\))
• Magnesium ion (\(Mg^{2+}\)), oxide ion (\(O^{2-}\))
• Aluminum ion (\(Al^{3+}\)), chloride ion (\(Cl^-\))
• Beryllium ion (\(Be^{2+}\)), phosphide ion (\(P^{3-}\))
• Calcium ion (\(Ca^{2+}\)), chloride ion (\(Cl^-\))

Step2: Criss - cross the charges

• For \(K^+\) and \(I^-\): \(K^+I^-\) → \(KI\)
• For \(Mg^{2+}\) and \(O^{2-}\): \(\frac{Mg^{2+}O^{2-}}{2}\) → \(MgO\)
• For \(Al^{3+}\) and \(Cl^-\): \(Al^{3+}(Cl^-)_3\) → \(AlCl_3\)
• For \(Be^{2+}\) and \(P^{3-}\): \(Be_3P_2\) (cross - multiply charges \(2\times3 = 6\), so \(Be_3P_2\))
• For \(Ca^{2+}\) and \(Cl^-\): \(Ca^{2+}(Cl^-)_2\) → \(CaCl_2\)

Answer:

1. \(KI\)
2. \(MgO\)
3. \(AlCl_3\)
4. \(Be_3P_2\)
5. \(CaCl_2\)