Oxygen compounds (-ite vs. -ate)

[JD Malana]

I know the suffixes -ite and -ate mean that a molecule is an oxygen compound (such as sulfite and sulfate) and that -ite's have the lesser amount of oxygen atoms between the two but how do we know how many oxygen's are involved? Is there a specific method to figuring that out?

[JD Malana]

Wait, correction: I read online that all -ate's have 3 oxygens except for sulfate and phosphate, which have 4 oxygens.
Furthermore, -ite's are all one less oxygen than the corresponding -ate so sulfite and phosphite will have 3 oxygens.

[ami patel]

Yes, that is correct. -Ate have three oxygens and -ite is just one less with the two exceptions that you mentioned.