What is s block elements?

• The elements of Group 1 and 2 of the periodic table constitute the s block elements.  
• The Group 1 s block elements are Lithium (Li), Sodium (Na), Potassium (k), Rubidium (Rb), Cesium (Cs), Francium (Fr).
• The Group 1 elements also called as Alkali Metals.
• The elements constituting Group 1 are reactive metals and form strongly alkaline oxides and hydroxides.  Therefore, they are called alkali metals.
• The are highly reactive and readily decompose water even at room temperature yielding metal hydroxides which are strong alkalies.