Question

In how many blocks have the elements of the long form of periodic table been divided? Name them.

Answer 1

Hint: In the long form of periodic table, the elements are arranged in the order of their atomic numbers. Atomic number of an element is equal to the number of electrons in an atom. Hence, there is a close relation between the electronic configuration of the elements and their position in the long form periodic table.
On the basis of electronic configuration, the elements have been categorized into four blocks in the periodic table.

Complete step by step answer:
On the basis of electronic configurations, the elements in the long form periodic table have been divided into four blocks. These are s, p, d, f-blocks.
Let us study the characteristics due to which the elements are divided into their respective blocks.
The nature of the sub-shell in which the last electron of that atom enters determines the block to which that element belongs:
s-block elements: Those elements (except He) in which the last electron enters into the s-subshell of the outermost main energy level, are called s-block elements.
The s-block is situated on the left-hand side of the periodic table. It contains 13 elements in two groups (1 and 2).
p-block elements: Those elements (except He) in which the last electron enters into the p-subshell of the outermost main energy level, are called p-block elements.
This block is situated on the right-hand side of the periodic table. It contains 30 elements in six groups 13-18 (except He).
d-block elements: Those elements in which the last electron enters into the d-subshell of the penultimate main energy level, are called d-block elements.
Elements of group 3-10 are d-block elements, also called transition elements, because these elements have partly filled d-orbitals in their elementary form. The d-block is situated between the s and p-blocks and contains 40 elements in four transition series.
f-block elements: Those elements in which the last electron enters into the f-subshell of the ante-penultimate main energy level, are called f-block elements.

This block is situated below s, d, and p-blocks. It contains 28 elements in two rows.

Note: The general configuration of the elements of the four blocks are as follows:
a. s-block elements: Their general configuration is \[n{{s}^{1-2}}\] (1 for group 1 and 2 for group 2), where n satisfies for the outermost shell. For example, sodium, lithium.
b. p-block elements: Their general configuration is \[(n-2)n{{s}^{2}}n{{p}^{1-6}}\]. For example, halogens.
c. d-block elements: The general configuration of these elements is \[(n-1){{d}^{1-10}}n{{s}^{1-2}}\]. For example, manganese, cobalt, nickel and chromium
d. f-block elements: Their general configuration is \[(n-2){{f}^{1-14}}(n-1){{d}^{0-1}}n{{s}^{2}}\]. For example, the lanthanides and actinides.