PLEASE ANSWER 3. What are the ions present in the compound Cuo? * (1 Point)
Cu+ and O-
Cu2+ and 02-
Cu2- and 02+
Cu+ and 02-

4al + 3o2 → 2al2o3 what does the "3" in front of o2 stand for? a) it indicates that there are 5 oxygen atoms after you add the coefficient and the subscript. b) it indicates that that there are are total of 6 oxygen atoms all bonded together as a single molecule. c) it indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction. d) it indicates that there are 3 separate oxygen molecules in the reaction.