Question

How is the modern periodic table different from the table Mendeleev proposed?

Answer 1

Hint:The classification of the element on the basis of their periodic properties, into groups and periods in a systematic way is termed as the periodic table.
The necessity of the classification is utmost and done in an organised way so as to get the idea about their size, properties and other crucial factors on the basis of which they differ from each other.

Complete step-by-step answer:Mendeleev was the reason behind the establishment of the first periodic law, which states that the “properties of elements are a periodic function of their atomic weights”. However, this periodic law has some disadvantages as the atomic mass is not a fundamental factor but the atomic number is. So, after a lot of hard work, he established a modified version of the previous periodic law, which is also called the modern periodic law, which says, “the chemical and physical properties of an element are periodic functions of their atomic numbers”. This modern periodic law helps modify the periodic table into a modern periodic table. The other differences between the modern periodic table and Mendeleev’s periodic table is given below in a tabular form.

Modern periodic table	Mendeleev’s periodic table
This periodic table takes in account the atomic numbers of the elements	This periodic table takes in account the atomic masses of the elements
This periodic table consists of eighteen groups and seven periods in it.	This periodic table consists of seven groups and six periods in it
The arrangement of the elements is solely based on the order of the atomic numbers of the element in increasing order	The arrangement of the elements is solely based on the order of their atomic masses in increasing order
The isotopes of the elements are being kept on the same place as the original element because of their same atomic numbers	The isotopes does not have any specific place in the Mendeleev’s periodic table.

Note:The modern periodic table differs from the Mendeleev’s periodic table in a number of ways, but the main difference between the two is that the Mendeleev’s periodic table arranges the elements on the basis of increasing order of their atomic masses.
While in case of the modern periodic table, the elements are placed on the basis of increasing order of their atomic numbers.