BLOCKS OF ELEMENTS

 Periodic table is divide into 4 blocks known as S, p, d, f blocks. The classification of the elements depends upon the type of sub-shell in which last electron of the element enters. 

S - Block elements 

The element in which last electron enters into s - subshell are called s - block element. 

The general electronic configuration of s - block elements are ns1-2 . 

The s - block elements are present in the left side of the periodic table. 

Group 1 and Group 2 elements as well as Helium of zero group are known as the s - block elements.

All s - block elements are normal elements.

Characteristics of s - block elements

(i) The elements have low ionization energy. 

(ii) They are soft metal having low melting and boiling point. 

(iii) They are highly reactive. 

(iv) They are good reducing agents. 

(v) They give to the flame. 

p - block elements

The elements in which last electrons enters into p - subshell are called p - block elements . 

The general electronic configuration of P - block elements are ns2 np1 - 6 . 

The P - block elements are present in extreme right of the periodic table, which consists of 6 groups i.e. 13 - 18. 

All P - block elements are normal or representative elements. 

Characteristics of p - block elements

(i) They have high ionization energy. 

(ii) They formed covalent compounds. When we go from left to right there is change form reducing to oxidizing character. 

d - block elements

The elements in which last electron enters into d - subshell are called d - block elements. 

The general electronic configuration of d - block elements are (n - 1) d 1 - 10 ns 1 - 2 . 

The d - block elements are present in the middle of the periodic table and consists of ten groups i.e.from group 3 to 12.

These elements are called transition elements. 

Characteristics of d - block elements

(i) Elements of d - block elements are usually metals and they have high boiling and melting point. 

(ii) Most of d - block elements are paramagnetic i.e. they are attracted towards magnetic field. 

(iii) d - block elements formed coloured compounds. 

(iv) Most of these elements from complexes. 

(v) They show variable oxidation state. 

f - block elements

The elements in which last electron enters into f - subshell are called f - block elements. 

General electronic configuration of f - block elements are (n - 2) f 1-14 (n - 1) d 0 or 1 ns1 . 

The f - block elements constituents lanthanides and Actinides. 

These elements are present in two rows below the periodic table. 

Lanthanides (atomic no.  57 - 71) are 4f - elements because here the last electron enters into 4f subshell. 

Actinides are 5f - elements (atomic no. 89 onwards) because the last electron enters into 5f - subshell. 

Characteristics of f - block elements

(i) f - block elements are heavy metals having high melting and boiling point. 

(ii) They show variable oxidation state. 

(iii) They formed coloured compounds.

(iv) Actinides are radio active in nature.