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

(N/A) Elements in which the last electron enters the $s$-orbital are known as $s$-block elements.
The elements of group $1$ (alkali metals) and group $2$ (alkaline earth metals),which have $ns^{1}$ and $ns^{2}$ outermost electronic configurations respectively,belong to the $s$-block.
Characteristics:
- They are all reactive metals with low ionization enthalpies.
- They readily lose their outermost electron$(s)$ to form $1+$ ions (alkali metals) or $2+$ ions (alkaline earth metals).
- Metallic character and reactivity increase as we move down the group.
- Due to high reactivity,they are never found in a pure state in nature.
- Compounds of $s$-block elements,with the exception of those of $Li$ and $Be$,are predominantly ionic.