Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?
- MgO < K2O < Al2O3 < Na2O
- K2O < Na2O < Al2O3 < MgO
- Na2O < K2O < MgO < Al2O3
- Al2O3 < MgO < Na2O < K2O
As metallic character of element attached to oxygen atom increases, the difference between the electronegativity values of element and oxygen increases and thus basic character of oxides increases and vice-versa.
Hence, the increasing correct order of basic nature is
Al2O3 < MgO < Na2O < K2O
The correct option is D.