Question

Name the following ionic compounds: (a) \(\mathrm{Li}_{2} \mathrm{O}\), (b) \(\mathrm{FeCl}_{3}\), (c) \(\mathrm{NaClO},(\mathbf{d}) \mathrm{CaSO}_{3},(\mathbf{e}) \mathrm{Cu}(\mathrm{OH})_{2},\), (f) \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}\), (g) \(\mathrm{Ca}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2}\), (h) \(\mathrm{Cr}_{2}\left(\mathrm{CO}_{3}\right)_{3},(\mathbf{i}) \mathrm{K}_{2} \mathrm{CrO}_{4},(\mathbf{j})\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}\).

Short answer

(a) Lithium oxide, (b) Iron (III) chloride, (c) Sodium hypochlorite, (d) Calcium sulfite, (e) Copper (II) hydroxide, (f) Iron (II) nitrate, (g) Calcium acetate, (h) Chromium (III) carbonate, (i) Potassium chromate, (j) Ammonium sulfate.

Step-by-step solution

Recognizing the Cation and Anion

For each compound, identify the cation (metal or NH4+) and the anion (non-metal or polyatomic ion). This will help guide the naming process based on standard nomenclature rules.

Naming Simple Ionic Compounds

For compounds like (a) \(\mathrm{Li}_{2} \mathrm{O}\), identify \(\mathrm{Li}^+\) as lithium and \(\mathrm{O}^{2-}\) as oxide. The compound is named lithium oxide.

Naming Ionic Compounds with Transition Metals

For (b) \(\mathrm{FeCl}_{3}\), identify iron as the cation. Since \(\mathrm{Fe}\) can have different charges, determine the charge by balancing with the anion \(\mathrm{Cl}^-\), resulting in iron (III) chloride.

Naming Compounds with Polyatomic Ions

For (c) \(\mathrm{NaClO}\), identify sodium as the cation and hypochlorite \(\mathrm{ClO}^-\) as the anion. Name the compound sodium hypochlorite.

Naming Compounds with Multiple Oxidation States

For (d) \(\mathrm{CaSO}_{3}\), recognize calcium as \(\mathrm{Ca}^{2+}\) and sulfite as \(\mathrm{SO}_{3}^{2-}\). Name the compound calcium sulfite. Similarly, for transition metals, determine the charge from the anion for the overall charge (e.g., (e) \(\mathrm{Cu(OH)}_2\) as copper (II) hydroxide).

Consideration for Polyatomic Ions and Transition Metals

For (f) \(\mathrm{Fe(NO}_{3})_{2}\), identify iron as the cation and nitrate \(\mathrm{NO}_{3}^-\) as the anion, resulting in iron (II) nitrate. Similarly, for other compounds, name the cation first, then the polyatomic anion: (g) \(\mathrm{Ca} \left(\mathrm{CH}_{3} \mathrm{COO} \right)_{2}\) is calcium acetate.

Naming Compounds Using Rules for Polyatomic and Complex Ions

For (h) \(\mathrm{Cr}_{2} \left(\mathrm{CO}_{3} \right)_{3}\), identify the naming as chromium (III) carbonate. Continue with the pattern to name (i) \(\mathrm{K}_{2} \mathrm{CrO}_{4}\) as potassium chromate, and (j) \((\mathrm{NH}_{4})_{2} \mathrm{SO}_{4}\) as ammonium sulfate.

Key concepts

Chemical Nomenclature

Chemical nomenclature is the system of naming chemical substances. It's essential for scientists to communicate clearly about compounds. For ionic compounds, this system involves identifying and naming the cation and anion that make up the compound.

• Simple Ionic Compounds: These consist of a metal and a non-metal. The metal's name comes first, followed by the non-metal with an "-ide" ending. For example, \(Li_2O\) is named lithium oxide.
• Complex Ionic Compounds: These involve polyatomic ions or transition metals with multiple possible charges. These compounds follow specific rules to ensure clarity in naming.

Consistent use of chemical nomenclature helps avoid confusion and ensures that everyone speaks the same language in chemistry.

Polyatomic Ions

Polyatomic ions are charged particles composed of two or more atoms covalently bonded together, acting as a single unit with a charge.

• Common Polyatomic Ions: Some examples include sulfate (\(SO_4^{2-}\)), nitrate (\(NO_3^{-}\)), and acetate (\(CH_3COO^{-}\)).
• Naming Conventions: When naming compounds with polyatomic ions, the name of the ion remains unchanged. For instance, \(NaClO\) is sodium hypochlorite, where hypochlorite refers to the polyatomic ion \(ClO^-\).

Recognizing and memorizing polyatomic ions is crucial for naming many ionic compounds correctly. Once you know the common ones, naming becomes much easier.

Transition Metals

Transition metals are elements found in the d-block of the periodic table. These metals are unique because they can have multiple oxidation states or charges. This characteristic affects how we name compounds that include them.

• Variable Oxidation States: For example, iron (\(Fe\)) can form ions with charges of +2 or +3. This property requires us to specify the charge in the compound's name, often using Roman numerals, such as iron (III) chloride for \(FeCl_3\).
• Naming Method: The charge of the transition metal in a compound is determined based on the charge of the anion it pairs with. Keeping track of these charges is key to correct chemical nomenclature.

Understanding transition metals and their varying charges can be challenging, but it's essential for correctly naming many compounds.

Oxidation States

Oxidation states indicate the degree of oxidation of an atom within a compound. It's a crucial concept for both naming and understanding the chemical behavior of compounds.

• Determining Oxidation States: In a neutral compound, the sum of all oxidation states must equal zero. For example, in \(Fe(NO_3)_2\), the total negative charge from \(NO_3^-\) ions is balanced by the positive charge of iron, giving iron an oxidation state of +2.
• Role in Nomenclature: Oxidation states help in naming compounds with transition metals. It's specified in the compound's name using Roman numerals.

Understanding oxidation states aids in the broader comprehension of chemical reactions and compound formation. It's a critical part of chemistry that ties into other concepts like oxidation-reduction reactions.