What are the s-block elements?
Group I A and IIA the alkaline metals and alkaline earth metals.
Group IA metals such as sodium, potassium, are elements that have valance electrons in the s orbitals.
Group II A metals such as magnesium, calcium are elements that have valance electrons in the s orbitals.
These are the alkali metals, and the alkaline earths.
And look at your Periodic Table; the leftmost COLUMN,
And the second-most column, Group 2, the so-called alkaline earths,