Answer:
co2 is a compound.
Step-by-step explanation:
Oxygen(O) is an element having atomic number 8 and mass number 16.
Carbondioxide is a compound formed by burning of carbon and organic compound and it is a colorless and odorless gas.
O2 is the molecular form of Oxygen.
Cobalt(Co) is an element having atomic number 27 and mass number 59.