Final answer:
The charge of the chlorate ion is different from the other chloro-oxyanions.
Step-by-step explanation:
Among the four oxyanions of chlorine, namely, chlorate, chlorite, hypochlorite, and perchlorate, the charge of the chlorate ion is different from the other chloro-oxyanions.
The chlorate ion (ClO3-) is an example of an -ate oxyanion and has a charge of -1, while the chlorite ion (ClO2-) and the hypochlorite ion (ClO-) are examples of -ite oxyanions, both with a charge of -1 as well.
On the other hand, the perchlorate ion (ClO4-) has a charge of -1 and also belongs to the -ate group.