Question

Fill in the blanks in the following table: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\\ \hline & & & \text { Lithium oxide } \\ \hline \mathrm{Fe}^{2+} & \mathrm{PO}_{4}^{3-} & & \\ \hline & & \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} & \\ \hline & & & \text { Copper(II) nitrate } \\ \hline \mathrm{Cr}^{3+} & \mathrm{I}^{-} & & \\ \hline & & \mathrm{MnClO}_{2} & \\ \hline & & & \text { Ammonium carbonate } \\ \hline & & & \text { Zinc perchlorate } \\ \hline \end{array} $$

Short answer

The completed table: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Li}^{+} & \mathrm{O}^{2-} & \mathrm{Li}_{2}\mathrm{O} & \text { Lithium oxide } \\ \hline \mathrm{Fe}^{2+} & \mathrm{PO}_{4}^{3-} & \mathrm{Fe}_{3}\left(\mathrm{PO}_{4}\right)_{2} & \text { Iron(II) phosphate } \\ \hline \mathrm{Al}^{3+} & \mathrm{SO}_{4}^{2-} & \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} & \text { Aluminum sulfate } \\ \hline \mathrm{Cu}^{2+} & \mathrm{NO}_{3}^{-} & \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2} & \text { Copper(II) nitrate } \\ \hline \mathrm{Cr}^{3+} & \mathrm{I}^{-} & \mathrm{CrI}_{3} & \text { Chromium(III) iodide } \\ \hline \mathrm{Mn}^{2+} & \mathrm{ClO}_{2}^{-} & \mathrm{MnClO}_{2} & \text { Manganese(II) chlorite } \\ \hline \mathrm{NH}_{4}^{+} & \mathrm{CO}_{3}^{2-} & \left(\mathrm{NH}_{4}\right)_{2}\mathrm{CO}_{3} & \text { Ammonium carbonate } \\ \hline \mathrm{Zn}^{2+} & \mathrm{ClO}_{4}^{-} & \mathrm{Zn}\left(\mathrm{ClO}_{4}\right)_{2} & \text { Zinc perchlorate } \\ \hline \end{array} $$

Step-by-step solution

Identify the missing information - Lithium oxide

We know the name is Lithium oxide. In this case, the cation is Lithium (Li) and the anion is oxide (O). We can now determine the valency of each and then write the formula. - Lithium (Li) has a valency of +1 - Oxide (O) has a valency of -2 To balance the positive and negative charges, the formula is Li_2O. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Li}^{+} & \mathrm{O}^{2-} & \mathrm{Li}_{2}\mathrm{O} & \text { Lithium oxide } \\ \hline \end{array} $$

Identify the missing information - Fe²⁺ and PO₄³⁻

In this case, we know the cation is iron (Fe²⁺) and the anion is phosphate (PO₄³⁻). We now determine the formula and name of the compound using these ions. Using the valencies, the formula will be Fe₃(PO₄)₂. Iron can form cations with multiple charges, so we need to specify the charge in the name. In this case, it is Iron(II) phosphate. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Fe}^{2+} & \mathrm{PO}_{4}^{3-} & \mathrm{Fe}_{3}\left(\mathrm{PO}_{4}\right)_{2} & \text { Iron(II) phosphate } \\ \hline \end{array} $$

Identify the missing information - $$\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$$

We are given the formula, which tells us that the cation is Aluminum (Al³⁺) and the anion is sulfate (SO₄²⁻). The name of the compound is Aluminum sulfate. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Al}^{3+} & \mathrm{SO}_{4}^{2-} & \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} & \text { Aluminum sulfate } \\ \hline \end{array} $$

Identify the missing information - Copper(II) nitrate

With the name Copper(II) nitrate, we know the cation is Copper (Cu²⁺) and the anion is nitrate (NO₃⁻). We can now determine the formula. Using the valencies, the formula is Cu(NO₃)₂. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Cu}^{2+} & \mathrm{NO}_{3}^{-} & \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2} & \text { Copper(II) nitrate } \\ \hline \end{array} $$

Identify the missing information - Cr³⁺ and I⁻

Here, we have the cation Chromium (Cr³⁺) and the anion iodide (I⁻). We determine the formula and name of the compound using these ions. The formula is CrI₃, and the name is Chromium(III) iodide. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Cr}^{3+} & \mathrm{I}^{-} & \mathrm{CrI}_{3} & \text { Chromium(III) iodide } \\ \hline \end{array} $$

Identify the missing information - $$\mathrm{MnClO}_{2}$$

We are given the formula $$\mathrm{MnClO}_{2}$$. The cation is Manganese (Mn²⁺) and the anion is chlorite (ClO₂⁻). The name of the compound is Manganese(II) chlorite. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Mn}^{2+} & \mathrm{ClO}_{2}^{-} & \mathrm{MnClO}_{2} & \text { Manganese(II) chlorite } \\ \hline \end{array} $$

Identify the missing information - Ammonium carbonate

Given the name Ammonium carbonate, the cation is ammonium (NH₄⁺) and the anion is carbonate (CO₃²⁻). Using the valencies, the formula is (NH₄)₂CO₃. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{NH}_{4}^{+} & \mathrm{CO}_{3}^{2-} & \left(\mathrm{NH}_{4}\right)_{2}\mathrm{CO}_{3} & \text { Ammonium carbonate } \\ \hline \end{array} $$

Identify the missing information - Zinc perchlorate

We know the name is Zinc perchlorate. The cation is Zinc (Zn²⁺) and the anion is perchlorate (ClO₄⁻). We can now determine the formula. Using the valencies, the formula is Zn(ClO₄)₂. The completed row is: $$ \begin{array}{|l|l|l|l|} \hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\ \hline \mathrm{Zn}^{2+} & \mathrm{ClO}_{4}^{-} & \mathrm{Zn}\left(\mathrm{ClO}_{4}\right)_{2} & \text { Zinc perchlorate } \\ \hline \end{array} $$

Key concepts

Cation and Anion Identification

Understanding the identities of cations and anions is essential when dealing with ionic compounds. A cation is a positively charged ion, often a metal, that has lost electrons. An anion, conversely, is a negatively charged ion, commonly a nonmetal, that has gained electrons. The importance of identifying these charged species lies in their role in determining the chemical formula and the correct name of an ionic compound.

To identify cations and anions, one often refers to the Periodic Table of Elements. Elements on the left side usually form cations, while those on the right tend to form anions. For instance, in the compound Lithium oxide, Lithium (Li) acts as the cation with a +1 charge, and oxide (O) is the anion with a -2 charge. This identification is the first crucial step in solving many chemistry problems, such as completing the given exercise.

Chemical Formula Determination

Once the cations and anions in a compound have been identified, the next step is to determine the correct chemical formula. This involves balancing the total positive and negative charges to ensure the compound is neutral. The valency, or oxidation state, of each ion plays an instrumental role in this process. The formula is deduced by finding the simplest ratio of ions that balances the charges.

For example, when combining Lithium (Li⁺) and oxide (O^2-), two lithium ions will balance one oxide ion, resulting in the formula \( Li_{2}O \). Similarly, in Iron(II) phosphate, the three Fe²⁺ ions combine with two PO₄^3- ions to achieve charge neutrality, giving us \( Fe_{3}(PO_{4})_{2} \). Balancing the charges often requires some practice to become proficient, especially when dealing with polyatomic ions or transition metals that can have various charges.

Ionic Compound Naming

Naming ionic compounds requires a clear understanding of both the ions involved and the rules of nomenclature. This process includes acknowledging the cation first, followed by the anion. For the compounds with a metal that has a fixed oxidation state, such as lithium oxide, the cation's simple elemental name is used followed by the anion name ending in '-ide'.

In compounds where the metal can have multiple charges, such as iron, copper, or chromium, the charge is specified using Roman numerals in parentheses. Thus, Copper(II) nitrate indicates a copper cation with a +2 charge and the nitrate anion. When naming compounds with polyatomic ions, the ion's name remains unchanged, as seen in Aluminum sulfate or Ammonium carbonate. Keeping these rules in mind helps in systematically naming a broad range of ionic compounds, which is crucial for clear communication in chemistry.