In `PO_(4)^(3-)` ion, the effective charge on each oxygen atom and P-O bond order respectively are

Options

A. `-0.75, 1.25`
B. `-0.75 , 1.0`
C. `-0.75 , 0.6`
D. `-3, 1.25`

Answer

To determine the effective charge on each oxygen atom and the P-O bond order in the \( PO_4^{3-} \) ion, we can follow these steps:

### Step 1: Determine the structure of \( PO_4^{3-} \)
The \( PO_4^{3-} \) ion consists of one phosphorus (P) atom and four oxygen (O) atoms. The phosphorus atom is centrally located, and the oxygen atoms are arranged around it. The ion has a total of three negative charges.

### Step 2: Calculate the effective charge on each oxygen atom
The effective charge (or formal charge) on an oxygen atom can be calculated using the formula:

\[ \text{Formal Charge} = \text{Valence Electrons} - \text{Non-bonding Electrons} - \frac{1}{2} \times \text{Bonding Electrons} \]

In the case of \( PO_4^{3-} \):
- Each oxygen atom typically has 6 valence electrons.
- In the structure, we have 3 oxygen atoms with a -1 charge (O⁻) and 1 oxygen atom with a double bond to phosphorus (P=O).

Given that there are 3 negative charges distributed among the 4 oxygen atoms, we can calculate the effective charge on each oxygen atom as follows:

\[ \text{Effective Charge} = \frac{\text{Total Negative Charge}}{\text{Number of Oxygen Atoms}} = \frac{-3}{4} = -0.75 \]

### Step 3: Determine the bond order of the P-O bond
The bond order can be calculated using the formula:

\[ \text{Bond Order} = \frac{\text{Total Number of Bonds}}{\text{Number of Resonating Structures}} \]

In \( PO_4^{3-} \):
- The total number of bonds between phosphorus and oxygen is 5 (1 double bond and 3 single bonds).
- The number of resonating structures can be determined by considering the different ways the negative charges can be distributed among the oxygen atoms. There are 4 possible resonating structures.

Thus, the bond order is calculated as follows:

\[ \text{Bond Order} = \frac{5}{4} = 1.25 \]

### Final Answer
- The effective charge on each oxygen atom is \( -0.75 \).
- The P-O bond order is \( 1.25 \).