For example, iron plus oxygen can become ferric oxide. Both elements change their names. The change is used to indicate the kind of bonding process that is taking place. When iron and oxygen become ferric oxide, the iron has lost electrons and the oxygen has gained the electrons that iron lost. <span>
2Cu + S ~~~> Cu2S Copper (C) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction.