3.0 s,p,d,f Block Elements

  Periodic Table

s-block Elements

• The elements of the periodic table in which the last electron enters in s-orbital, are called s-block elements.
• $s$-Orbital can accommodate a maximum of two electrons.
• Their general formulae are $ns^1$ and $ns^2$ respectively, where n=(1 to 7),
• $I A$ group elements are known as alkali metals because they react with water to form alkali. $II A$ group elements are known as alkaline earth metals because their oxides react with water to form alkali and these are found in the soil or earth.
• The total number of $s$ block elements are 14.
• $F{r^{87}}$and $R{a^{88}}$ are radioactive elements while H and He are gaseous elements.
• $Cs$ and $Fr$ are liquid elements belonging to s-block.