Which statement correctly describes the phosphate ion, [tex]\( PO_4^{3-} \)[/tex]?

A. It is composed of one phosphorus atom and four oxygen atoms covalently bonded together, and there is a -3 charge distributed over the entire ion.

B. It is composed of one phosphorus atom and four oxygen atoms covalently bonded together, and there is a -3 charge on the phosphorus atom.

C. It is composed of one phosphorus atom and four oxygen atoms ionically bonded together, and there is a -3 charge distributed over the entire ion.

D. It is composed of one phosphorus atom and four oxygen atoms ionically bonded together, and there is a -3 charge on the phosphorus atom.



Answer :

To determine which statement correctly describes the phosphate ion, [tex]\(PO_4^{3-}\)[/tex], let's break down the characteristics of the ion step-by-step.

1. The composition of the phosphate ion:
- The phosphate ion [tex]\( PO_4^{3-} \)[/tex] is composed of one phosphorus (P) atom and four oxygen (O) atoms. This matches the empirical formula provided: [tex]\( P \)[/tex] and [tex]\( 4 \times O \)[/tex].

2. The type of bonding in the phosphate ion:
- In [tex]\(PO_4^{3-}\)[/tex], the phosphorus atom is covalently bonded to the four oxygen atoms. Covalent bonding involves the sharing of electron pairs between atoms. Thus, this rules out any statement mentioning ionic bonds.

3. The distribution of charge on the phosphate ion:
- The overall charge on the phosphate ion is -3. This charge is distributed over the entire ion rather than being localized on the phosphorus atom alone. Therefore, any statement that implies the charge is exclusively on the phosphorus atom is incorrect.

Given these points, we can evaluate the given statements:

1. "It is composed of one phosphorus atom and four oxygen atoms covalently bonded together, and there is a -3 charge distributed over the entire ion."
- This statement is correct as it accurately describes the composition, type of bonding, and charge distribution in the phosphate ion.

2. "It is composed of one phosphorus atom and four oxygen atoms covalently bonded together, and there is a -3 charge on the phosphorus atom."
- This statement is incorrect because the charge is not localized on the phosphorus atom.

3. "It is composed of one phosphorus atom and four oxygen atoms ionically bonded together, and there is a -3 charge distributed over the entire ion."
- This statement is incorrect because the bonding in [tex]\(PO_4^{3-}\)[/tex] is covalent, not ionic.

4. "It is composed of one phosphorus atom and four oxygen atoms ionically bonded together, and there is a -3 charge on the phosphorus atom."
- This statement is incorrect because both the type of bonding (ionic instead of covalent) and the charge distribution (localized on the phosphorus atom) are incorrect.

Therefore, the correct statement that describes the phosphate ion [tex]\(PO_4^{3-}\)[/tex] is:
"It is composed of one phosphorus atom and four oxygen atoms covalently bonded together, and there is a -3 charge distributed over the entire ion."