Answer:
It's a Ionic compound
Step-by-step explanation:
To tell if CaO (Calcium oxide) is ionic or covalent (also called molecular) we look at the Periodic Table that and see that Ca is a metal and O is a non-metal. When we have a metal and a non-metal the compound is usually considered ionic.
Because we have a metal and non-metal in CaO there will be a difference in electronegativity between the metal and non-metal. This difference results in an electron(s) being transferred from the metal (lower electronegativity) to the non-metal (higher electronegativity). The results in the metal becoming a postitive ion and the non-metal a negative ion. The two opposite charges are attracted and form the ionic bond between atoms in Calcium oxide.