Which of the following is a metalloid?

Which of the following is the most electropositive element?

Which of the following is the correct order of acidic strength?

The elements $X$,$Y$,$Z$,and $T$ have the indicated electronic configurations. Starting with the innermost shell,which is the most metallic element?

Which of the following is/are amphoteric oxide$(s)$?

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 that lies immediately below this element in the periodic table?