# What are the s-block elements?

Aug 16, 2017

Group I A and IIA the alkaline metals and alkaline earth metals.

#### Explanation:

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.

Aug 16, 2017

And look at your Periodic Table; the leftmost COLUMN, $L i , N a ,$
$K , R b , C s , F r$ are the alkali metals; i.e. this is Group 1 of the Periodic Table, whose members have a single VALENCE electron, i.e. $\text{s-electrons}$.
And the second-most column, Group 2, the so-called alkaline earths, $B e , M g , C a , S r , B a , R a$, have a complete $\text{s-valence}$ shell. And thus both the Group 1 and Group 2 elements constitute the $\text{s-block}$.
Hydrogen, $Z = 1$, is a bit of a special case. Its metallic properties are only manifested under special circumstances, and many Periodic Tables offset hydrogen from the alkali metals.