1. The problem statement, all variables and given/known data Write a balanced equation for: 1. the reaction of chromium with sulfur 2. the reaction of bismuth with oxygen 2. Relevant equations Chromium is a transition metal and sulfur has a 2- charge. 3. The attempt at a solution For the first one, I'm thinking that since sulfur has a 2- then chromium must have a 2+ charge so it would form a product of CrS. I thought it would just be Cr + S ----> CrS That's before balancing of course but that's not the answer either. It's supposed to be Cr + S ----> Cr2S3 (before balancing) Why are there subscripts? The second one makes absolutely no sense to me because O is 2- and Bi is I believe 3-.