Question

drag the ions together in such a way as to make a rectangle, from top down, in the \build model\ portion of the table below, then fill in the rest of the table. see the sample completed table here:

\

$$\begin{tabular}{|c|c|c|c|} \\hline compound name & built model & cation to anion ratio & compound formula \\\\ \\hline aluminum oxide & \\begin{tabular}{c} \\text{al}^{3+} \\\\ \\text{al}^{3+} \\end{tabular}$$

\

$$\begin{tabular}{c} \\text{o}^{2-} \\\\ \\text{o}^{2-} \\\\ \\text{o}^{2-} \\end{tabular}$$

& 2 : 3 & \text{al}_2\text{o}_3 \\\\
\hline
\end{tabular}

\

$$\begin{tabular}{|c|c|c|c|} \\hline compound name & built model & cation to anion ratio & compound formula* \\\\ \\hline sodium sulfide & \\text{na}^+ & ? : ? & ?_? ?_? \\\\ \\hline \\end{tabular}$$

*if only one ion is needed in a formula, it is left off, but for this practice you will need to type in the quantity, even a 1.

Explanation:

⚡ Using what you learned: formation of ionic and covalent bonds

Step 1: Determine the charges of the ions

Identify the charges of the given cation and anion:

• Cation: Sodium ion, \(\text{Na}^+\) (charge of \(+1\))
• Anion: Sulfide ion, \(\text{S}^{2-}\) (charge of \(-2\))

Step 2: Balance the charges to find the ratio

To form a neutral ionic compound, the total positive charge must equal the total negative charge:

• Each \(\text{Na}^+\) provides \(+1\) charge.
• Each \(\text{S}^{2-}\) provides \(-2\) charge.

We need two \(\text{Na}^+\) ions to balance one \(\text{S}^{2-}\) ion:

$$ 2 \times (+1) + 1 \times (-2) = 0 $$

Thus, the cation to anion ratio is:

$$ 2 : 1 $$

Step 3: Write the compound formula

Using the ratio of \(2\) sodium ions to \(1\) sulfide ion, and following the instruction to include the quantity even if it is \(1\):

• Sodium symbol and quantity: \(\text{Na}_2\)
• Sulfide symbol and quantity: \(\text{S}_1\)

Combining them gives:

$$ \text{Na}_2\text{S}_1 $$

Answer:

• cation to anion ratio: \(2 : 1\)
• Compound formula: \(\text{Na}_2\text{S}_1\)