Question

Provide the formula for each of the following ternary ionic compounds: (a) manganese(II) acetate (b) copper(II) chlorite (c) tin(II) phosphate (d) iron(III) hypochlorite

Short answer

(a) Mn(C₂H₃O₂)₂, (b) Cu(ClO₂)₂, (c) Sn₃(PO₄)₂, (d) Fe(ClO)₃.

Step-by-step solution

Understanding Ternary Ionic Compounds

Ternary ionic compounds consist of three elements and generally include a metal and a polyatomic ion. Identifying the cation (metal) charge and the polyatomic ion is critical for writing the formulas.

Identifying Cations and Polyatomic Anions

In each compound, identify the cation and its charge from the compound name, and the associated polyatomic anion: (a) Manganese(II) has a charge of +2. (b) Copper(II) has a charge of +2. (c) Tin(II) has a charge of +2. (d) Iron(III) has a charge of +3.

Writing Formulas Using Charges

Balance the charge of the cation with the charge of the polyatomic anion to write the correct formula for each compound: (a) Acetate is C₂H₃O₂⁻: Mn(C₂H₃O₂)₂. (b) Chlorite is ClO₂⁻: Cu(ClO₂)₂. (c) Phosphate is PO₄³⁻: Sn₃(PO₄)₂. (d) Hypochlorite is ClO⁻: Fe(ClO)₃.

Finalizing Formulas

Check each formula for correctness by ensuring the sum of the charges equals zero: (a) Mn(C₂H₃O₂)₂: Manganese charge +2, two acetate charges -2. (b) Cu(ClO₂)₂: Copper charge +2, two chlorite charges -2. (c) Sn₃(PO₄)₂: Three tin charges +6, two phosphate charges -6. (d) Fe(ClO)₃: Iron charge +3, three hypochlorite charges -3.

Key concepts

Ternary Ionic Compounds

Ternary ionic compounds are fascinating because they consist of three different elements, usually combining a metal ion and a polyatomic ion. These compounds are a step up from binary ionic compounds, which only contain two elements. To understand ternary ionic compounds, it's important to identify the combination of a cation (which is typically a metal) and a polyatomic anion.

Examples of ternary ionic compounds include substances like manganese(II) acetate and copper(II) chlorite. For each example, the first part of the name refers to the metal ion, and the Roman numeral indicates the charge of this cation. The second part often involves the name of a polyatomic anion, such as acetate or chlorite. Recognizing the components in the name of a ternary compound helps us predict its chemical behavior and write the correct chemical formula.

Cation and Anion Identification

In ternary ionic compounds, identifying the cation and anion is crucial for determining the correct chemical formula. The cation is typically a metal ion and is presented in the compound's name with its charge in Roman numerals, such as manganese(II), copper(II), tin(II), or iron(III). These numerals tell us the positive charge on the metal ion:

• Manganese(II) carries a +2 charge.
• Copper(II) has a +2 charge.
• Tin(II) carries a +2 charge.
• Iron(III) has a +3 charge.

On the other hand, polyatomic anions like acetate (C₂H₃O₂⁻), chlorite (ClO₂⁻), phosphate (PO₄³⁻), and hypochlorite (ClO⁻) consist of collections of atoms bonded together that carry an overall negative charge. Knowing the charge on these polyatomic anions is equally important:

• Acetate carries a -1 charge.
• Chlorite carries a -1 charge.
• Phosphate carries a -3 charge.
• Hypochlorite carries a -1 charge.

Identifying and understanding these ions is the first step in writing the correct formula for any ternary ionic compound.

Charge Balancing

Charge balancing is the final step in correctly writing the formula for ternary ionic compounds. Each compound must be neutral, which means the total positive charge from the cations must equal the total negative charge from the anions.

For example, consider manganese(II) acetate. Manganese has a +2 charge, while each acetate carries a -1 charge. To balance these charges, two acetate ions are needed, resulting in the formula Mn(C₂H₃O₂)₂. Similarly, for iron(III) hypochlorite, iron(III) has a +3 charge, and each hypochlorite has a -1 charge. Three hypochlorites are needed to balance one iron(III), giving the formula Fe(ClO)₃.

To sum up the process:

• Determine the charge of the cation from its Roman numeral.
• Identify the charge of the polyatomic anion.
• Balance these charges so the total equals zero, forming a neutral compound.

This careful balancing of charges ensures that the formulas are correct, maintaining the chemical principles that govern ionic compounds.