Question

Write formulas for all of the compounds that can be made by combining the cations \(\mathrm{NH}_{4}^{+}\) and \(\mathrm{Ni}^{2+}\) with the anions \(\mathrm{CO}_{3}^{2-}\) and \(\mathrm{SO}_{4}^{2-}.\)

Short answer

The compounds are - \\(\mathrm{(NH}_4)_2\mathrm{CO}_3\\), - \\(\mathrm{(NH}_4)_2\mathrm{SO}_4\\), - \\(\mathrm{NiCO}_3\\), and - \\(\mathrm{NiSO}_4\\).

Step-by-step solution

Identify Cations and Anions

First, note the given cations: ammonium \(\mathrm{NH}_4^+\) and nickel(II) \(\mathrm{Ni}^{2+}\). The anions provided are carbonate \(\mathrm{CO}_3^{2-}\) and sulfate \(\mathrm{SO}_4^{2-}\). Each cation will be paired with each anion to form different compounds.

Form Compound with Ammonium and Carbonate

Combine the cation \(\mathrm{NH}_4^+\) with the anion \(\mathrm{CO}_3^{2-}\). To create a neutral compound, balance the charges: need two ammonium ions for each carbonate ion to form \(\mathrm{(NH}_4)_2\mathrm{CO}_3\).

Form Compound with Ammonium and Sulfate

Combine the cation \(\mathrm{NH}_4^+\) with the anion \(\mathrm{SO}_4^{2-}\). Similarly, to balance the charges, use two ammonium ions per sulfate ion to form \(\mathrm{(NH}_4)_2\mathrm{SO}_4\).

Form Compound with Nickel(II) and Carbonate

Combine the cation \(\mathrm{Ni}^{2+}\) with the anion \(\mathrm{CO}_3^{2-}\). Both have a charge of 2, so one nickel ion pairs with one carbonate ion to form \(\mathrm{NiCO}_3\).

Form Compound with Nickel(II) and Sulfate

Combine the cation \(\mathrm{Ni}^{2+}\) with the anion \(\mathrm{SO}_4^{2-}\). Again, the charges balance one-to-one, resulting in \(\mathrm{NiSO}_4\).

Key concepts

Ionic Compounds

Ionic compounds are a class of chemical compounds made up of positively charged ions (cations) and negatively charged ions (anions). These ions form due to the transfer of electrons between atoms, resulting in charged particles. Typically, ionic compounds consist of metals and non-metals or polyatomic ions. When these oppositely charged ions come together, they form an electrically neutral compound. Ionic compounds are held together by strong electrostatic forces known as ionic bonds, which contribute to the formation of crystalline structures. For instance, in the provided exercise, we looked at ammonium and nickel(II) cations combining with carbonate and sulfate anions to form various ionic compounds.

Charge Balance

A fundamental principle in the formation of ionic compounds is ensuring overall charge neutrality. This means that the total positive charge must equal the total negative charge in the compound. Let's consider this rule with ammonium and carbonate ions. Ammonium \(\text{NH}_4^+\) carries a +1 charge, while carbonate \(\text{CO}_3^{2-}\) carries a -2 charge. To balance these, we need two ammonium ions for every carbonate ion, resulting in a neutral compound, \(\text{(NH}_4\text{)}_2\text{CO}_3\). Similarly, when nickel(II) \(\text{Ni}^{2+}\) combines with sulfate \(\text{SO}_4^{2-}\), both ions have a charge of 2, so one nickel pairs with one sulfate, forming the neutral ionic compound \(\text{NiSO}_4\). Charge balance ensures stability in the resulting compounds.

Cation and Anion Combination

Creating ionic compounds involves choosing appropriate cations and anions and matching them to form neutral combinations. In our exercise, we started with given cations: ammonium \(\text{NH}_4^+\) and nickel(II) \(\text{Ni}^{2+}\). We paired each cation with the anions carbonate \(\text{CO}_3^{2-}\) and sulfate \(\text{SO}_4^{2-}\). The task was to ensure the charges were balanced for stable compound formation. For example, ammonium can pair with carbonate by using two ammonium ions per carbonate ion. These pairings result in the production of different compounds like \(\text{(NH}_4\text{)}_2\text{CO}_3\) and \(\text{NiCO}_3\), both of which demonstrate balanced ionic interactions.

Chemical Formula Writing

Writing chemical formulas for ionic compounds involves using symbols to represent the types of ions involved and their relative numbers. This requires understanding how to balance the charges of the ions. In our examples, we wrote the formula for ammonium sulfate as \(\text{(NH}_4\text{)}_2\text{SO}_4\), indicating two ammonium cations for every sulfate anion. Meanwhile, nickel(II) carbonate is written as \(\text{NiCO}_3\), showing a one-to-one ratio of cations to anions. Understanding the charges and how they combine is essential for writing accurate chemical formulas. This task is vital for chemists to ensure proper communication about the composition of compounds.