Choose the typical element.

Which of the following orders is correct?

The correct order of acid strength is

Classify oxides and provide examples for each type.

Among the statements $(I-IV)$,the correct ones are:
$(I)$ $Be$ has smaller atomic radius compared to $Mg$.
$(II)$ $Be$ has higher ionization enthalpy than $Al$.
$(III)$ Charge/radius ratio of $Be$ is greater than that of $Al$.
$(IV)$ Both $Be$ and $Al$ form mainly covalent compounds.

$Mg^{2+}$ is . . . . . . than $Al^{3+}$.