Question

Complete the table by filling in the formula for the ionic compound formed by each pair of cations and anions, as shown for the first pair.$$ \begin{array}{|l|l|l|l|l|} \hline \mathrm{lon} & \mathrm{Na}^{+} & \mathrm{Ca}^{2+} & \mathrm{Fe}^{2-} & \mathrm{Al}^{3+} \\ \hline \mathrm{O}^{2-} & \mathrm{Na}_{2} \mathrm{O} & & & \\ \hline \mathrm{NO}_{3}^{-} & & & & \\ \hline 9 \mathrm{O}_{4}^{2-} & & & & \\ \hline \mathrm{AsO}_{4}{ }^{3-} & & & & \\ \hline \end{array} $$

Short answer

The completed table with the formulas for ionic compounds is as follows: $$ \begin{array}{|l|l|l|l|l|} \hline \mathrm{Ion} & \mathrm{Na}^+ & \mathrm{Ca}^{2+} & \mathrm{Fe}^{2+} & \mathrm{Al}^{3+} \\ \hline \mathrm{O}^{2-} & \mathrm{Na}_2 \mathrm{O} & CaO & FeO & Al_2O_3 \\ \hline \mathrm{NO}_3^- & NaNO_3 & Ca(NO_3)_2 & Fe(NO_3)_2 & Al(NO_3)_3 \\ \hline \mathrm{SO}_4^{2-} & Na_2SO_4 & CaSO_4 & FeSO_4 & Al_2(SO_4)_3 \\ \hline \mathrm{AsO}_4^{3-} & Na_3AsO_4 & Ca_3(AsO_4)_2 & Fe_3(AsO_4)_2 & AlAsO_4 \\ \hline \end{array} $$

Step-by-step solution

Complete the row for O^2- ion

To find the formula for each compound, balance the charges of the ions. In each case, make sure the overall charge is 0. For Ca^2+ and O^2- ions: Ca^2+ has a charge of +2, and O^2- has a charge of -2. One Ca^2+ ion and one O^2- ion will balance each other out. Thus, the formula is \( CaO \). For Fe^2+ and O^2- ions: Fe^2+ has a charge of +2, and O^2- has a charge of -2. Similar to the previous case, one Fe^2+ ion and one O^2- ion balance each other out. Thus, the formula is \( FeO \). For Al^3+ and O^2- ions: Al^3+ has a charge of +3, and O^2- has a charge of -2. To balance the charges, we need 2 Al^3+ ions (+6 charge) and 3 O^2- ions (-6 charge). Thus, the formula is \( Al_2O_3 \).

Complete the row for NO3^- ion

Follow the same procedure to balance the charges for the given ions. For Na^+ and NO3^- ions: Na^+ has a charge of +1, and NO3^- has a charge of -1. One Na^+ ion and one NO3^- ion balance each other out. Thus, the formula is \( NaNO_3 \). For Ca^2+ and NO3^- ions: Ca^2+ has a charge of +2, and NO3^- has a charge of -1. We need 2 NO3^- ions (-2 charge) to balance the charge of Ca^2+. Thus, the formula is \( Ca(NO_3)_2 \). For Fe^2+ and NO3^- ions: Both Fe^2+ and NO3^- ions have charges of +2 and -1, respectively. Similar to the previous case, we need 2 NO3^- ions (-2 charge) to balance the charge of Fe^2+. Thus, the formula is \( Fe(NO_3)_2 \). For Al^3+ and NO3^- ions: Al^3+ has a charge of +3, and NO3^- has a charge of -1. We need 3 NO3^- ions (-3 charge) to balance the charge of Al^3+. Thus, the formula is \( Al(NO_3)_3 \).

Complete the row for SO4^2- ion

Continue balancing the charges for the given ions. For Na^+ and SO4^2- ions: Na^+ has a charge of +1, and SO4^2- has a charge of -2. We need 2 Na^+ ions (+2 charge) to balance the charge of SO4^2-. Thus, the formula is \( Na_2SO_4 \). For Ca^2+ and SO4^2- ions: Both Ca^2+ and SO4^2- ions have charges of +2 and -2, respectively. One Ca^2+ ion and one SO4^2- ion will balance each other out. Thus, the formula is \( CaSO_4 \). For Fe^2+ and SO4^2- ions: Both Fe^2+ and SO4^2- ions have charges of +2 and -2, respectively. One Fe^2+ ion and one SO4^2- ion will balance each other out. Thus, the formula is \( FeSO_4 \). For Al^3+ and SO4^2- ions: Al^3+ has a charge of +3, and SO4^2- has a charge of -2. To balance the charges, we need 2 Al^3+ ions (+6 charge) and 3 SO4^2- ions (-6 charge). Thus, the formula is \( Al_2(SO_4)_3 \).

Complete the row for AsO4^3- ion

Complete the last row by balancing the charges for the given ions. For Na^+ and AsO4^3-ions: Na^+ has a charge of +1, and AsO4^3- has a charge of -3. We need 3 Na^+ ions (+3 charge) to balance the charge of AsO4^3-. Thus, the formula is \( Na_3AsO_4 \). For Ca^2+ and AsO4^3- ions: Ca^2+ has a charge of +2, and AsO4^3- has a charge of -3. To balance the charges, we need 3 Ca^2+ ions (+6 charge) and 2 AsO4^3- ions (-6 charge). Thus, the formula is \( Ca_3(AsO_4)_2 \). For Fe^2+ and AsO4^3- ions: Fe^2+ has a charge of +2, and AsO4^3- has a charge of -3. To balance the charges, we need 3 Fe^2+ ions (+6 charge) and 2 AsO4^3- ions (-6 charge). Thus, the formula is \( Fe_3(AsO_4)_2 \). For Al^3+ and AsO4^3- ions: Al^3+ has a charge of +3, and AsO4^3- has a charge of -3. One Al^3+ ion and one AsO4^3- ion will balance each other out. Thus, the formula is \( AlAsO_4 \).

Key concepts

Chemical Formula

When forming ionic compounds, understanding the creation of their chemical formulas is like solving a puzzle. These formulas represent the simplest ratio of the ions involved. They tell us how many of each type of ion are needed to create a balanced compound.

For each ionic compound, the positive and negative charges must balance to zero. This is because ionic compounds, unlike molecules, are electrically neutral overall. Therefore, knowing the charge of each ion helps in determining the number of ions needed. For instance, the compound formed between sodium (Na\(^+\)) and oxygen (O\(^{2-}\)) is sodium oxide, written as Na\(_2\)O. Here, two sodium ions (each with +1 charge) balance one oxide ion (with -2 charge), achieving a neutral balance.
In summary, creating ionic compounds’ chemical formulas relies on balancing charges and understanding the ion ratio in the compound. Each formula provides a snapshot of the ionic interaction and the proportions needed to achieve neutrality.

Ions Balancing

Balancing ions is essential to forming ionic compounds correctly. It's all about ensuring that the total positive charge equals the total negative charge in the compound. This is key to maintaining the electrical neutrality of the compound.

### Steps for Balancing IonsTo balance ions:

• Identify the charges on the cation (positive ion) and the anion (negative ion).
• Use the charges to determine the ratio of ions necessary for a neutral compound.
• Write the chemical formula using the ratios to reflect this charge balance.

Let's take calcium ions (Ca\(^{2+}\)) and nitrate ions (NO\(_3^-\)). Calcium has a +2 charge, and nitrate has a -1 charge. To balance these, you need two nitrate ions for every calcium ion, resulting in the formula Ca(NO\(_3\))\(_2\).

Understanding and applying this principle of ion balancing helps in systematically building accurate chemical formulas for ionic compounds.

Cations and Anions

In the world of chemistry, cations and anions are the building blocks of ionic compounds. Cations are positive ions, typically metals, because they lose electrons. Anions, on the other hand, have gained electrons and are negative, often made up of non-metals.

### Understanding Cations- **Cations** have a positive charge.- Metals like sodium (Na\(^+\)), calcium (Ca\(^{2+}\)), and aluminum (Al\(^{3+}\)) become cations by losing electrons.### Understanding Anions- **Anions** carry a negative charge.- These include non-metals like oxygen (O\(^{2-}\)), and complex ions such as nitrate (NO\(_3^-\)) or phosphate (AsO\(_4^{3-}\)).

When these oppositely charged ions come together, they form ionic bonds, creating stable compounds like sodium nitrate (NaNO\(_3\)) or aluminum oxide (Al\(_2\)O\(_3\)). This attraction between cations and anions is fundamental to the formation of ionic compounds, explaining much of their behavior and properties.