"No, no, nooo... Wrong answer. The valences of phosphorus are -3, 3, 4, and 5, and besides failing and incorrectly telling me the corresponding ones for sulfur, you've just earned yourself five minutes of tickling on your right foot, which, on the other hand, will be great to emulate the pressure of a real exam while you explain to me based on the valences of chromium and oxygen how they combine to form chromium oxide, and what the difference is compared to chromic acid... Unless you want your left foot to join the tickling party, and the duration of this increases to fifteen minutes... I already told you that studying for exams doesn't have to be boring..." 🙃