Oxygen is the 8th element in the Periodic Table and has O for the symbol. It is a non-metal.
Oxygen has several compounds. The most common is water, also known as dihydrogen monoxide (H2O), which has one oxygen and two hydrogen atoms. Water is the number one essential need for life and covers 71% of the Earth's surface.
If Oxygen were exposed to a metal, an oxide would be created out of that metal. An example would be Lithium exposed to Oxygen forming Lithium Oxide.