Which group element from the following achieves noble gas configuration after gaining two electrons?

The correct order of acid strength is

Which of the following orders correctly represents the increasing acidic strength of the given acids?

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

Which one of the following reactions does not occur?

$Mg$ and $Li$ are similar in their properties due to