Question

Why is it that the s-block elements never occur in free state/nature? What are their usual modes of occurrence and how are they generally prepared?

Answer 1

Hint: The s-block elements are the elements in the first two columns and helium. The s-block elements are alkali and alkali earth metals, they are highly reactive. Helium here can be taken as an exception as it has a complete electronic configuration.

Complete answer:
The main reason that s-block elements never occur in free state/nature is that these are alkali and alkali earth metals which are highly reactive. The high reactivity comes from their low ionization energy.
They have either one or two electrons in their outermost orbit so they tend to form stable products as soon as they get another element wanting electrons. Thus, s-block elements are never found in a free state in nature.
They are always found in formed compounds, such as silicates, carbonates, oxides, etc. As the elements are highly reactive, they are easily accepting elements or compounds.
These formed compounds of s-block elements are found in earth’s crust.
As the s-block elements are not found in a free state in nature, they have to be formed by carrying out certain methods. Generally group I metals of s-block are separated from their compounds by electrolysis method.
The separation of sodium metal by electrolysis method is shown below.
\[NaCl\xrightarrow{{}}N{{a}^{+}}+C{{l}^{-}}\]
The sodium metal gets collected at the cathode of the voltaic cell.
At cathode:
\[N{{a}^{+}}+{{e}^{-}}\xrightarrow{{}}Na\]
Thus, many such metals are obtained by electrolysis methods.

Note:
Here helium cannot be included as it has a complete electronic configuration. Due to the complete electronic configuration, it does not form products with any element and can be obtained in a free state in nature. But, helium is rare and is formed naturally by decomposition of radioactive elements.