Depending on the type of orbital in which the differentiating electron enters, the elements are classified into *, p, d and f - block elements.
s - block elements :
(1) The elements of group IA and IIA belongs to *-block.
(2) Their differentiating electron enters into *-orbital.
(3) Except hydrogen, all the *-block elements are metals.
(4) Their general electronic configuration is ns1 to ns2.
p-block elements :
(1) The elements of group IIIA to VIIIA belongs to p-block.
(2) This differentiating electron enters into p-orbital.
(3) Their general electronic configuration is ns2np1 to ns2 np6.
(4) The only p-block element in which the differentiating electron does not enter into p-orbital is He.
(5) p-block contains metals, non-metals and metalloids.
d-block elements :
(1) The elements of group IB to VIIIB belongs to d-orbital.
(2) Their differentiating electron enters into (n – 1) d orbital.
(3) All the d-block elements are metals.
(4) Their general electronic configuration is (n – 1) d1 – 10 ns1 or 2) The d-block elements are placed in between the * and p-block elements.
f-block elements :
( 1) The Lanthanides and Actinides which are placed below the periodic table are known as f-block elements.
(2) Their differentiating electron enters into the (n – 2) f orbital.
Advantages of this kind of classification :
(i) By knowing the block of the element, it is very easy to study the general behaviour and important properties of the elements.
Ex : If the element belongs to *-block, it means it must have 1 or 2 electrons in outer-most shell. Hence it must have low value of IE, strongly metallic and electropositive character and form cations easily.
(ii) It is easy to recognise the valence subshell of the atom.
