Select the correct answer.

What is the chemical formula of the compound copper(II) phosphate? Use the list of polyatomic ions and the periodic table to help you answer.

A. [tex]Cu _3\left( PO _4\right)[/tex]
B. [tex]Cu \left( PO _4\right)_2[/tex]
C. [tex]Cu _2\left( PO _4\right)_2[/tex]
D. [tex]Cu _3\left( PO _4\right)_2[/tex]



Answer :

Sure, let's determine the chemical formula of copper(II) phosphate step-by-step.

1. Identify the charges of the ions involved:
- Copper(II) ion has a charge of [tex]\( +2 \)[/tex]: [tex]\( \text{Cu}^{2+} \)[/tex].
- Phosphate ion has a charge of [tex]\( -3 \)[/tex]: [tex]\( \text{PO}_4^{3-} \)[/tex].

2. Determine the least common multiple (LCM) of the charges (2 and 3):
- The LCM of 2 and 3 is 6. This means we want the total positive charges and the total negative charges to sum up to 6 so that the compound is neutral.

3. Calculate the number of each ion needed to balance the charges:
- To reach a total positive charge of +6 using copper ions ([tex]\( \text{Cu}^{2+} \)[/tex]), we need 3 copper ions: [tex]\( 3 \times +2 = +6 \)[/tex].
- To reach a total negative charge of -6 using phosphate ions ([tex]\( \text{PO}_4^{3-} \)[/tex]), we need 2 phosphate ions: [tex]\( 2 \times -3 = -6 \)[/tex].

4. Write the chemical formula:
- Since we need 3 copper ions and 2 phosphate ions, the chemical formula for copper(II) phosphate is [tex]\( \text{Cu}_3(\text{PO}_4)_2 \)[/tex].

Thus, the correct answer is:
[tex]\[ \text{D. } \text{Cu}_3(\text{PO}_4)_2 \][/tex]