Final answer:
The formula unit for the compound formed by the interaction of K+ and PO4^3- is K3PO4. This formula reflects the need for three potassium ions to balance the charge of one phosphate ion, resulting in an electrically neutral compound.
Step-by-step explanation:
The formula unit for the compound formed when potassium ions (K+) interact with phosphate ions (PO43-) can be determined by balancing the charges of the ions to create an electrically neutral compound. Since the potassium ion has a +1 charge and the phosphate ion has a -3 charge, three potassium ions are needed to balance the charge of one phosphate ion. Thus, the formula unit for this compound is K3PO4.
Key concepts in forming ionic compounds:
- Ionic compounds must be electrically neutral.
- Monoatomic and polyatomic ions are treated as discrete units.
- Parentheses are used to denote the polyatomic ion when more than one is needed to balance the charge.
In this situation, there is no need for parentheses because only one phosphate ion is needed to combine with three potassium ions to achieve charge neutrality, resulting in K3PO4.