Question

Where is the charge located in a polyatomic ion?

Answer 1

Hint: By convention, the electron's charge is regarded as negative. By convention, an electron's negative charge is equal to and opposite that of charged proton(s) deemed positive. An ion's net charge is non-zero because its total number of electrons is greater than its total number of protons.

Complete Step By Step Answer:
Atomic or monatomic ions are made up of only one atom, whereas molecular or polyatomic ions are made up of two or more atoms. In the case of physical ionisation in a fluid (gas or liquid), spontaneous molecule collisions produce "ion pairs," each of which contains a free electron and a positive ion. Chemical reactions, such as the dissolution of a salt in liquids, or other methods, such as sending a direct current through a conducting solution or ionisation, can also produce ions.
A polyatomic ion, also known as a molecular ion, is a covalently linked set of two or more atoms, or a metal complex, that behaves as a single unit and has a net charge greater than zero. This chemical species is an ion, as opposed to a molecule, which has a net charge of zero.
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Because the charge isn't situated somewhere in particular, we draw square brackets around polyatomic ions and place the charge there when drawing dot-and-cross diagrams. Remember that charge is just the difference between the number of protons in an atom's nucleus and the number of electrons in its shell. Each has a positive or negative charge that is spread among the nuclei and electron shells of the polyatomic ion.
Hence the charge is present nowhere.

Note:
An anion is a negatively charged ion with more electrons than protons, whereas a cation is a positively charged ion with less electrons. Cations and anions are attracted to one other by their opposing electric charges and easily form ionic compounds.