Question

Write a short note on the modern periodic table

Answer 1

Mendeleev’s periodic table was based on atomic weight. In 1913, Moseley from his studies on X-rays found that the atomic number is the more fundamental property of an element than its atomic mass. Thus, atomic number was adopted as the basis of modern periodic table. Moseley’s periodic law was then formulated as:

The properties of an element are a periodic function of its atomic number.

The periodic table based on this law is known as the modern periodic table. This periodic table is also known as Long or Extended Form of the periodic table. In the Mendeleev’s periodic table the subgroups A and B have been kept together giving rise to short periods. In the modern periodic table, the subgroups A and B have been separated so that the periods have been extended. Therefore, the older version of the periodic table is also called the short form of periodic table and the modern periodic table is called the long or extended form of the periodic table.

Answer 2

ModernPeriodicTable​ 

✌️✔️Classification of elements resulting from an arrangement of the elements in an increasing order of their atomic numbers is the Modern Periodic Table. 

✌️✔️Properties of the elements can be predicted more accurately with the help of the modern periodic table formed on the basis of atomic numbers. The modern Periodic Table is also called the long form of the periodic table.

✌️✔️Modern Periodic Table contains Seven horizontal rows called the periods 1 to 7. 
Similarly, the eighteen vertical colomns in this table are the groups 1 to 18.

✌️✔️Apart from these seven rows , two rows are shown separately at the bottom of periodic table. These are called Lanthanides series and actinide series respectively. 

✌️✔️There are 118 boxes in the periodic table which means there are 118 places for elements in the modern periodic table. 

This is what the modern periodic table is.

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