The metal oxides are

Metal oxides are basic in nature.

Metal oxides are compounds in which there are two elements, i.e., a metal and an oxygen atom. Sodium oxide ($N{a}_{2}O$), magnesium oxide ($MgO$), calcium oxide ($CaO$), etc. are a few examples. These are basic because when they interact with weak acids, salt and water are produced, demonstrating the basic nature of metal oxides.