In the following,the element with the highest electropositivity is

The atomic numbers of the metallic and non-metallic elements which are liquid at room temperature respectively are

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 reactivity of the following compounds toward water is in the order:

Which of the following pairs has both members from the same group of the periodic table?

Which of the following is a normal element?