Answer:
1. Magnesium + Oxygen --> Magnesium oxide
2.Iron + Oxygen --> Iron oxide
3.Copper + Oxygen --> Copper oxide
Explanation:
When an Element such as Magnesium or any other Elements are reacted eith Oxygen it forms an Oxide.
If you ever need the symbol equation here it is too :
1. Mg + O --> MgO
2.Fe + O --> FeO
3.Cu + O--> CuO
