The compound formed between potassium and chlorate ion is KClO₃, which is called potassium chlorate. Here's how we determine the formula:

* Potassium (K): Potassium is an alkali metal in group 1 of the periodic table, meaning it has a +1 charge when it forms an ion (K⁺).

* Chlorate ion (ClO₃⁻): The chlorate ion has a -1 charge.

To form a neutral compound, the charges must balance. Since potassium has a +1 charge and chlorate has a -1 charge, one potassium ion (K⁺) combines with one chlorate ion (ClO₃⁻) to form KClO₃.