Which of the following are amphoteric oxides?

An element of group $2$ forms a covalent oxide which is amphoteric in nature and dissolves in water to give an amphoteric hydroxide. Identify the element and write chemical reactions of the hydroxide of the element with an alkali and an acid.

Which of the following is true for $Magnesium$ $(Mg)$?

Which element from the following exhibits a diagonal relationship with beryllium $(Be)$?

$Be(OH)_2$ is insoluble in water while $Ba(OH)_2$ is highly soluble due to:

$X$-ray tube windows are made using which of the following metals?