What is the correct formula for sodium phosphate? (LO 2.24) (a) Na₃PO₄ (b) Na₃P (c) NaPO₄ (d) Na(PO₄)₂

Verified step by step guidance

1. Identify the ions involved in forming sodium phosphate. Sodium (Na) is a cation with a +1 charge, and phosphate (PO4) is an anion with a -3 charge.
2. Determine the correct ratio of sodium ions to phosphate ions to balance the charges. Since sodium has a +1 charge and phosphate has a -3 charge, you need three sodium ions to balance one phosphate ion.
3. Write the chemical formula by placing the cation first followed by the anion. Include the necessary subscripts to indicate the number of each ion in the formula.
4. Check the chemical formula to ensure that the total charge is zero, indicating that the charges are balanced.
5. Compare the formula you derived with the options given in the problem to find the correct answer.

Key Concepts

Ionic Compounds

Ionic compounds are formed when metals transfer electrons to nonmetals, resulting in the formation of positively charged cations and negatively charged anions. In the case of sodium phosphate, sodium (Na) is a metal that forms a cation (Na+), while phosphate (PO4) is a polyatomic anion. Understanding the nature of these ions is crucial for determining the correct formula of the compound.

Polyatomic Ions

Polyatomic ions are ions composed of two or more atoms covalently bonded together, which carry a net charge. The phosphate ion (PO4) carries a -3 charge, which is essential for balancing the charges when combined with sodium ions. Recognizing the charge of polyatomic ions helps in writing the correct chemical formulas for compounds.

Chemical Formula Writing

Writing chemical formulas involves combining the symbols of the elements or ions in a compound while ensuring that the overall charge is neutral. For sodium phosphate, three sodium ions (Na+) are needed to balance the -3 charge of one phosphate ion (PO4). This results in the formula Na3PO4, which reflects the correct stoichiometry of the compound.