Question

what is the chemical formula? (you have the charges/use the crisscross method)
ca₃(po₄)₂
ca₃po₂
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Explanation:

Step1: Determine the charges

Calcium (\(Ca\)) has a charge of \(+2\), and the phosphate ion (\(PO_{4}\)) has a charge of \(-3\).

Step2: Apply the criss - cross method

Swap the magnitudes of the charges. So, we get \(Ca_{3}(PO_{4})_{2}\). The subscript for \(Ca\) is \(3\) (from the charge of phosphate) and the subscript for \(PO_{4}\) is \(2\) (from the charge of calcium). Also, we need to put parentheses around \(PO_{4}\) because it is a polyatomic ion.

Answer:

\(Ca_{3}(PO_{4})_{2}\) is the correct chemical formula. So the first option (\(Ca_{3}(PO_{4})_{2}\)) is the answer.