Final answer:
The polyatomic ion ClO3- is called the chlorate ion, which has one more oxygen atom than the chlorite ion (ClO2-) and one less than the perchlorate ion (ClO4-).
Step-by-step explanation:
The polyatomic ion with the formula ClO3- is known as the chlorate ion. This ion is part of a series of halogen oxyanions that include hypochlorite (ClO-), chlorite (ClO2-), and perchlorate (ClO4-). The suffix '-ate' signifies that this ion has a higher number of oxygen atoms compared to the '-ite' ion, in this case, chlorite. Unlike monatomic ions which end with '-ide', polyatomic ions have distinct names that can include the suffixes '-ate' and '-ite', each indicating a different number of oxygen atoms attached to the central atom.
Remember, when you're naming monatomic anions, you replace the end of the element’s name with '-ide', such as 'chloride' from chlorine. On the other hand, polyatomic ions often have oxygen and are named with '-ate' or '-ite', depending on the number of oxygen atoms present. The chlorate ion is one example of a polyatomic ion with the '-ate' suffix, where chlorine is bonded to three oxygen atoms and carries a negative one charge.