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

Set up the charge balance equation: (number of Cu^{2+} ions) \(\times\) (+2) + (number of P^{3-} ions) \(\times\) (-3) = 0.

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.