Question

metallic oxide are acidic in nature ,? why

Answer 1

because they contain less atomic Mass

Answer 2

Non-metals react with oxygen in the air to produce non-metal oxides. Here are two examples for the non-metals carbon and sulphur. Non-metal oxides such as sulphur dioxide and nitrogen oxide are responsible for acid rain. They dissolve in the water in the clouds to form acidic solutions.

Metal oxides which exhibit this behavior are termed basic oxides because they act as bases. The oxides of nonacidic cations are so water reactive that they are seldom seen. These oxides cannot be prepared by dehydrating the hydroxide at high temperature. The oxides of feebly acidic cations are more common