Write three general characteristics of the elements of s-block of the periodic table which distinguish them from the elements of the other blocks.

The three general characteristics are:

(1)The compounds of the s-block elements are mainly ionic.

(2)The valency is equal to the group number.

(3) Due to low ionization energy, s-block elements are good reducing agents.

The alkali metals have low densities. Explain. ?

The alkali metals have low densities due to their large atomic sizes. In fact, Li, Na and K are even lighter than water.

What is the most reactive alkali metal and why?

The most reactive alkali metal is cesium due to its lowest first ionization enthalpy and lowest electronegativity.