2 Matching 5 points What is the oxidation number of Pin Mg_(3)(PO_(4))_(2) square p square

To determine the oxidation number of phosphorus (P) in \( Mg_3(PO_4)_2 \), we need to follow these steps:<br /><br />1. **Identify the compound and its components:**<br /> - The compound is \( Mg_3(PO_4)_2 \).<br /> - It consists of magnesium (Mg) and the phosphate ion (PO₄).<br /><br />2. **Assign known oxidation numbers:**<br /> - Magnesium (Mg) is an alkaline earth metal and typically has an oxidation number of +2.<br /> - The overall charge of the phosphate ion (PO₄) is -3.<br /><br />3. **Set up the equation:**<br /> - The compound \( Mg_3(PO_4)_2 \) is neutral, so the sum of the oxidation numbers must be zero.<br /> - Let the oxidation number of phosphorus (P) be \( x \).<br /><br /> The formula for the phosphate ion is \( PO_4 \), which has a charge of -3. Since there are two phosphate ions in the compound, the total contribution from the phosphate ions is \( 2 \times (-3) = -6 \).<br /><br /> The total contribution from the magnesium ions is \( 3 \times (+2) = +6 \).<br /><br /> The sum of the oxidation numbers must be zero:<br /> \[<br /> 3(+2) + 2(x) = 0<br /> \]<br /><br />4. **Solve for \( x \):**<br /> \[<br /> 6 + 2x = 0<br /> \]<br /> \[<br /> 2x = -6<br /> \]<br /> \[<br /> x = -3<br /> \]<br /><br />Therefore, the oxidation number of phosphorus (P) in \( Mg_3(PO_4)_2 \) is \(-3\).<br /><br />So, the correct answer is:<br />\[<br />\boxed{-3}<br />\]