Question

what are the exceptions for criss cross method​

Answer 1

Answer:

Step-by-step Sort of. When you crisscross the oxidation numbers to make the subscripts, you may need to reduce the subscripts to the smallest possible values.

For instance, suppose you are writing the formula for tin(IV) oxide. When you crisscross the +4 and -2 you end up with Sn2O4, which should be reduced to SnO2.