Which one of the following is an $s$-block element?

The valence shell electronic configuration of alkali metals is

Alkali metals are powerful reducing agents because

Which of the following is thermally decomposable?

$2Na_2O \overset{400 \ ^oC}{\rightleftharpoons} A + 2Na$
$A + SO_2 \to Na_2SO_4$
$A + CO \to Na_2CO_3$
In the above reaction,$A$ is:

Lattice energy of alkali metal chlorides follows the order