3. BaS. Let's say you have Hydrogen (H) 1 and Fluorine (F) -1. Then it will be 1+ -1=0. So you don't put a subscript. It will just be HF.
If it does not equal to 0 then you put the subscript to balance it out until you get 0.
4. a. Sulfide.
c. Tin dichloride. (There are endings depending on the number.) Chloride has a subscript of 2.
5. b. The ending is chloride just like 4.
