To determine which of the given options is a polyatomic ion, let's review each choice:
A. [tex]\(PO_4^{3-}\)[/tex]
- This is the phosphate ion. It consists of one phosphorus atom and four oxygen atoms, and it carries a charge of 3-.
- Since it is composed of multiple atoms and has a net charge, it is classified as a polyatomic ion.
B. [tex]\(S^{2-}\)[/tex]
- This is the sulfide ion. It consists of only one sulfur atom and carries a charge of 2-.
- Because it is made of just one atom, it is a monatomic ion, not a polyatomic ion.
C. [tex]\(HCl\)[/tex]
- This is hydrogen chloride. It is a neutral molecule consisting of one hydrogen atom and one chlorine atom.
- It does not carry a charge and is not an ion.
D. [tex]\(N_2\)[/tex]
- This is nitrogen gas. It is a neutral molecule consisting of two nitrogen atoms.
- It does not carry a charge and is not an ion.
Among the given options, the only choice that is a polyatomic ion is:
A. [tex]\(PO_4^{3-}\)[/tex]
Therefore, the correct answer is A. [tex]\(PO_4^{3-}\)[/tex].
