Question

What are the advantages and disadvantages of modern periodic table?

Answer 1

The important advantages of the modern periodic table are given below :


This classification is based on the atomic number which is a more fundamental property of the elements.

Since this classification is based on the atomic number and not on the atomic mass, the position of placing isotopes at one place is fully justified.

It is easy to remember and reproduce.

The systematic grouping of elements into four blocks; s, p, d and f has made the study of the elements more simple.

The position of some elements which were misfit on the basis of atomic mass is now justified on the basis of atomic number. For example, argon precedes potassium because argon has atomic number 18 and potassium has 19.

The lanthanoids and actinoids which have properties different from other groups are placed separately at the bottom of the periodic table.

The main defects of this table are :


The position of hydrogen is not settled. It resembles with alkali metals as well as halogens. However, it has been placed with alkali metals.

Lanthanoids and actinoids have not been accommodated in the main body of the periodic table.

Answer 2

Merits of the modern periodic table:
The classification is based on the atomic number of elements which is more fundamental than the atomic weight

In this periodic table, the position of an element is related to the electronic configuration of the atom. Elements belonging to the same group possess same no.of electrons in their valance shells and show similar characteristics.(check the attachement for the examples)

Variation of chemical properties along a period is correlated with gradual filling of electrons in a particular shell in the period.

In this table inert gases are placed at the end of each period which is very logical because valance shells have octet configuration. The inertness can also be explained in terms of electronic configuration.

Due to the separation of two subgroups, dissimalr elements are not placed together.

Different types of elements like active metals, transition metals, nonmetals, metalloids ,inner transition elements etc have their specific locations


Defects:
The position of hydrogen remained controversial because it's valance electron shows similarities of both alkali metals and halogens.

Lanthanides and actinides couldnt be placed in the main body of the periodic table

It doesn't reflect the exact distribution of electrons of some of the transition and intertransition elements