Question

Name the following ionic compounds: \((\mathbf{a}) \mathrm{KCN},(\mathbf{b}) \mathrm{NaBrO}_{2},\) (c) \(\mathrm{Sr}(\mathrm{OH})_{2}\) (d) CoTe, (e) \(\mathrm{Fe}_{2}\left(\mathrm{CO}_{3}\right)_{3},\) (f) \(\mathrm{Cr}\left(\mathrm{NO}_{3}\right)_{3}\) (h) \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) (g) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{3},\) (i) \(\mathrm{KMnO}_{4},(\mathbf{j}) \mathrm{Ag}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\).

Short answer

The short answer to the naming of the given ionic compounds is as follows: (a) Potassium Cyanide (b) Sodium Bromite (c) Strontium Hydroxide (d) Cobalt Telluride (e) Iron(III) Carbonate (f) Chromium(III) Nitrate (g) Sodium Dihydrogen Phosphate (h) Ammonium Sulfite (i) Potassium Permanganate (j) Silver(I) Dichromate

Step-by-step solution

Identify metal, nonmetal, and polyatomic ions in the formula

The first step in naming an ionic compound is identifying the metal (cation) and non-metal (anion) along with any present polyatomic ions.

Name the cation and anion according to their respective elements or polyatomic ions

Name the cation (metal ion) and the anion (non-metal or polyatomic ion). For metals with only one charge, simply use the metal's name. For metals with multiple charges, use Roman numerals to indicate the charge. For non-metals, change their ending to "-ide." For polyatomic ions, use their designated name.

Combine the names of the cation and anion to complete naming the compound

After naming both cation and anion, combine their names to give the complete name of the ionic compound. Now, let's apply these steps to each compound: a) KCN Step 1: Cation: K (Potassium), Anion: CN (Cyanide) Step 2: K (Potassium), CN (Cyanide) Step 3: Potassium Cyanide b) NaBrO₂ Step 1: Cation: Na (Sodium), Anion: BrO₂ (Bromite) Step 2: Na (Sodium), BrO₂ (Bromite) Step 3: Sodium Bromite c) Sr(OH)₂ Step 1: Cation: Sr (Strontium), Anion: OH (Hydroxide) Step 2: Sr (Strontium), OH (Hydroxide) Step 3: Strontium Hydroxide d) CoTe Step 1: Cation: Co (Cobalt), Anion: Te (Tellurium) Step 2: Co (Cobalt), Te (Telluride) Step 3: Cobalt Telluride e) Fe₂(CO₃)₃ Step 1: Cation: Fe (Iron), Anion: CO₃ (Carbonate) Step 2: Fe (Iron), CO₃ (Carbonate) - Iron has a multiple possible charges, so we need to determine the charge using the chemical formula. For this compound, we see that there is a balanced charge: 2(Fe³⁺)+3(CO₃²⁻). Therefore, Iron must have a charge of +3. Step 3: Iron(III) Carbonate f) Cr(NO₃)₃ Step 1: Cation: Cr (Chromium), Anion: NO₃ (Nitrate) Step 2: Cr (Chromium), NO₃ (Nitrate) - Since there are 3 nitrates and chromium is in a 3+ state, using the chemical formula, we have Cr³⁺+3(NO₃⁻) Step 3: Chromium(III) Nitrate g) NaH₂PO₄ Step 1: Cation: Na (Sodium), Anion: H₂PO₄ (Dihydrogen phosphate) Step 2: Na (Sodium), H₂PO₄ (Dihydrogen phosphate) Step 3: Sodium Dihydrogen Phosphate h) (NH₄)₂SO₃ Step 1: Cation: NH₄ (Ammonium), Anion: SO₃ (Sulfite) Step 2: NH₄ (Ammonium), SO₃ (Sulfite) Step 3: Ammonium Sulfite i) KMnO₄ Step 1: Cation: K (Potassium), Anion: MnO₄ (Permanganate) Step 2: K (Potassium), MnO₄ (Permanganate) Step 3: Potassium Permanganate j) Ag₂Cr₂O₇ Step 1: Cation: Ag (Silver), Anion: Cr₂O₇ (Dichromate) Step 2: Ag (Silver), Cr₂O₇ (Dichromate) - Silver has only one charge, which is +1. Step 3: Silver(I) Dichromate

Key concepts

Chemical Naming

Chemical naming is the process of giving a distinct name to chemical compounds based on their composition and structure. This relies on systematic rules set by the International Union of Pure and Applied Chemistry (IUPAC). By following these rules, we can ensure everyone understands the compound's formula and structure. Here's a simplified rundown:

• Identify Cation and Anion: Determine the positively charged ion (cation) and the negatively charged ion (anion) in the compound.
• Name the Cation: Use the element's name if it's a metal with a definite charge. If it has multiple charges, specify it with Roman numerals inside parentheses after the element's name.
• Name the Anion: For non-metals, change their suffix to "-ide." For polyatomic ions, use their conventional names as they appear in tables or lists.
• Combine the Names: Simply put the cation name first, followed by the anion name to complete the chemical name.

This systematic approach helps avoid confusion in communicating what a specific chemical compound is made of.

Cation and Anion Identification

In chemical formulas, identifying the cation and anion is crucial for proper naming and understanding the compound’s properties. A cation is typically a metal that has lost electrons, giving it a positive charge. Conversely, an anion has gained electrons, so it carries a negative charge. Recognizing these ions awards insight into the compound's behavior and interaction with other chemicals.

Metal Cations

• Most metal elements form cations.
• Common cations include Na⁺ (Sodium), K⁺ (Potassium), and Ca²⁺ (Calcium).

Non-metal Anions

• Non-metals often form anions by gaining electrons.
• Examples include Cl⁻ (Chloride) and Br⁻ (Bromide).

Polyatomic Ions

Polyatomic ions are charge-bearing entities made of multiple atoms. Having different metals and non-metal combinations, they often retain conventional names. Examples include carbonate (CO₃²⁻) and nitrate (NO₃⁻). They play essential roles in forming complex ionic compounds.

Chemical Formulas

Chemical formulas represent how compounds are composed, showing the types and numbers of atoms present. For ionic compounds, the formula is key to determining the charges of cations and anions involved. Balancing charges is necessary for overall neutral charge in compounds.

Understanding Formulas

• Symbols and Numbers: Formulas use element symbols and subscript numbers to show composition, such as H₂O for water indicating two hydrogen atoms and one oxygen atom.
• Charge Balance: The total positive charge from the cations must balance the total negative charge from the anions, ensuring the compound is electrically neutral.

Examples in Practice

• The formula CaCl₂ shows each calcium ion (Ca²⁺) pairs with two chloride ions (Cl⁻) to balance charges.
• In Fe₂(CO₃)₃, two Iron(III) ions (Fe³⁺) pair with three carbonate ions (CO₃²⁻) to balance the total charge.

Chemical formulas provide a clear depiction of how elements and ions are configured in a compound, essential for predicting reactions and properties.