$A$ pink colored salt on dry heating becomes blue in colour. The salt may contain:

In which of the following is a metal-to-metal bond present?

An alloy which does not contain copper is

Give a brief account of the abundance of alkali metals and alkaline earth metals in the Earth's crust.

Give the correct order of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.
$(I)$ Number of $S-S$ bonds in $H_{2}S_{n}O_{6}$ is $(n - 1)$.
$(II)$ When $F_{2}$ reacts with water,it gives $HF, O_{2}$ and $O_{3}$.
$(III)$ $LiNO_{3}$ and $BaCl_{2}$ compounds are used in fireworks.
$(IV)$ $Be$ and $Mg$ hydrides are ionic and polymeric.

Write a note on $s$-block elements of the periodic table.