Explanation:
Ions are the species that contain either a positive or negative charge.
For example,
,
,
,
are all ions.
Whereas when two or more different atoms are bonded together then the product formed is known as a compound.
For example,
is a compound.
On the other hand, species that do not contain any charge are known as neutral species.
For example, fe, Zn, Cu are all neutral atoms.
Thus, we can conclude that items which represent the ions are as follows.
,
,
, and 