Which of the following is the correct chemical formula for the ionic compound formed between Cu^{2+} and P^{3-} ions?

• A. Cu_2P
• B. CuP
• C. Cu_3P_2
• D. Cu_2P_3

Answer: (C)

Verified step by step guidance

1. Identify the charges on the ions involved: copper ion is Cu^{2+} and phosphide ion is P^{3-}.
2. Determine the ratio of ions needed to balance the total positive and negative charges so that the compound is electrically neutral.
3. Set up the charge balance equation: (number of Cu^{2+} ions) \times (+2) + (number of P^{3-} ions) \times (-3) = 0.
4. Find the smallest whole number ratio of Cu^{2+} to P^{3-} ions that satisfies the charge balance. This involves finding the least common multiple of the charges 2 and 3.
5. Write the chemical formula using the ratio found, placing the number of each ion as subscripts: Cu_{3}P_{2}.