If a charge of 40kC flows through an electrical heater and the amount of energy converted into heat is 10MJ. Calculate the potential difference across the ends of the heater

Iron is a transition metal with multiple oxidation numbers. (answer the following) a. what is the iron (ii) ion? how does it differ from the iron (iii) ion? b. if iron were to bond with oxygen, predict the formula for each oxidation number of iron. c. how would each formula be named?