Question

Modern periodic table is divided into:

Answer 1

Periodic table is a tabular arrangement in which elements are arranged according to their atomic numbers. The organization of the periodic table is used to derive relationships between the various chemical properties and behavior of the elements. Every element has a unique atomic number representing the number of protons in its nucleus.

Complete answer:
Elements having similar outer electronic configurations in their atoms are arranged in vertical columns which are referred to as groups, while the horizontal rows are known as periods.
There are $7$ periods and $18$ groups in the modern periodic table.
The elements are further divided into $4$ blocks.
The elements of group $1$ which are also called alkali metals and group $2$ are called alkaline earth metal having $n{s^1}$ and $n{s^2}$ outermost electronic configuration belongs to $s -$ block elements.
Group $13-18$ constitutes the $p$ -block elements; moreover, p-block and s block elements together are called representative elements or main group elements. The general outermost electronic configuration of $p$ -block elements are $n{s^2} - n{p^6}$ . Group $18$ elements are called noble gases, group $17$ elements are called halogens while group $16$ elements are called chalcogens.
The elements group $3$ to $12$ having general outermost electronic configuration $(n - 1){d^{1 - 10}}n{s^{0 - 2}}$ constitute the $d$ - block elements are also called transition elements
$f -$ block elements also known as inner transition metal constitute the elements of the last two bottom rows of the periodic table i.e. lanthanide series and actinide series. The general outermost electronic configuration of $f$ -block elements are $(n - 2){f^{1 - 14}}(n - 1){d^{0 - 1}}n{s^2}$ .

Note:
Antoine Lavoiser published a list of $33$ chemical elements and grouped them into gases, metals and nonmetals then Johann wolfgang Dobereiner observed many elements can be grouped into triads based on their chemical properties. Then A.E.B de Chancourtois arranged the elements in the increasing atomic weight and used a cylindrical table to show the recurrence of periodic properties.