How can chemical equations be classified?
There are six main types of equations, grouped by how they're formatted and what kind of reaction occurs.
Oxygen (diatomic, subscript is 2) combined with a metal, to make the metal oxide. There is only one O in the oxide.
Hydrogen is transferred from one to the other.
If any of these formats don't make sense, the best resource is your textbook used in class. The Acid-Base you may or may not use with the rest of these, it fits more into the Acids and Bases topic. Remember to balance all equations.