Which properties in a period indicate the chemical reactivity of elements?

The most electropositive element possesses the electronic configuration

Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?

With the help of the following reactions,arrange the metals $A$,$B$,$D$,and $E$ in decreasing order of their reactivity:
$(I)$ $B + ANO_3 \longrightarrow BNO_3 + A$
$(II)$ $A + HCl \longrightarrow ACl + \frac{1}{2} H_2$
$(III)$ $D + ECl \longrightarrow DCl + E$
$(IV)$ $D + HNO_3 \longrightarrow$ $H_2$ gas is not evolved

The chemical properties of $Li$ and $Mg$ are similar because:

Which of the following is the correct order of acidic strength for $Al_2O_3$,$SiO_2$,$P_2O_3$,and $SO_2$?