Which of the following is an amphoteric oxide?

In a periodic table, how does the basic character of oxides vary?

In which of the following,the elements $Al, B, Mg$ and $K$ are correctly arranged in the increasing order of their metallic character?

The electronic configuration of an element is $1s^2, 2s^2 2p^6, 3s^2 3p^3$. What is the atomic number of the element which is just below the above element in the periodic table?

Explain the periodic properties of elements and their reactivity trends in the periodic table.

Which of the following oxides is the most amphoteric?