Select all ionic compounds in which the number of anions present is three.

ammonium sulfite

ammonium perchlorate

cadmium phosphate

ammonium iodate

ammonium sulfate

barium bromide

none

How can u tell???

2 answers

I would start with writing the chemical formulas. For instance, barium bromide BaBr2
it has three ions.
I will be happy to critique your work.
How about doing your own homework