Final answer:
In a solution of Na3PO4, the present ions are sodium ions (Na+) and phosphate ions (PO43-). The compound dissociates into three sodium ions and one phosphate ion in water. It is crucial to consider polyatomic ions as a single unit when writing chemical formulas.
Step-by-step explanation:
In a solution of Na3PO4, or sodium phosphate, there are two types of ions present: sodium ions (Na+) and phosphate ions (PO43-). When sodium phosphate dissolves in water, it dissociates into its constituent ions. Each formula unit of sodium phosphate generates three sodium ions and one phosphate ion upon dissolution. The ions present in the solution can be expressed as follows: 3 Na+ (aq), and 1 PO43- (aq). These are the species that would be present in an aqueous solution of sodium phosphate before considering any potential reactions with other substances in solution.
Writing formulae of compounds with polyatomic ions requires special attention to ensure that the ion remains as a single intact unit. If there are multiple polyatomic ions, they are enclosed in parentheses with a subscript outside to indicate the quantity. However, in the case of sodium phosphate, this is not necessary as there is only one polyatomic ion in the formula unit. It's important to remember to balance charges, but in the dissociation of Na3PO4, the total charge is already balanced with three Na+ ions balancing one PO43- ion.