Question

Write the merits of the modern periodic table over Mendeleev’s Periodic table.

Answer 1

Hint: Periodic table is a collection of many different elements which are arranged in particular manner according to their physical and chemical properties. In periodic table vertical columns are named as groups and these group elements have the same electronic configuration or same number of valence electrons in the outer shell.

Complete answer:
Dmitri lvanovich Mendeleev was the first scientist who gave the proper arrangement of the elements in the periodic table. Before Mendeleev’s, John Newlands put forward his law of octet but it cannot apply to all elements. The basic concept of Mendeleev’s was that the physical and chemical properties of the elements are depending on their atomic masses and he arranged the known elements in this order itself. At that time, he was working on only 63 elements which are known. He also treated the formula of hydrides and oxides as one of the basic criteria for categorization. The law he stated is followed as “the properties of elements are the periodic function of their atomic masses”.

Series	Group 1	Group 2	Group 13	Group 14	Group 15
1	H=1
2	Li=7	Be=9.1	B=11	C=12	N=14
3	Na=23	Mg=24.4	Al=27	Si=28	P=31
4	K=39.1	Ca=40		Ti=48.1	V=51.2

But, if we want to compare between modern periodic table and Mendeleev’s periodic table we should have knowledge about modern periodic table.
Mendeleev is the inventor of the modern periodic table. It was used to correctly predict elements that hadn’t been discovered. The periodic table is periodically revised. In modern periodic tables we follow the concept of increasing atomic number; it means we arrange the elements in increasing order of their atomic number. And mostly, metals are present in the periodic table. Now, let’s see the merits of modern periodic table over Mendeleev’s periodic table:
i) Elements are arranged on the basis of their increasing atomic number.
ii) Isotopes of an element can be placed with their parent element.
iii) Lanthanides and actinides are placed separately.
iv) Modern periodic table also justify the fact that \[Ar\] and \[K\] have the same atomic mass.
v) Rows of periodic table are known as periods and columns are known as groups.
vi) All elements can be classified as metals, metalloids or nonmetals.

Note: However, isotopes have not been given spatial places in the periodic table because of their similar properties. So this was a drawback of Mendeleev’s periodic table. Modern periodic table is based upon the arrangement of elements in increasing order of atomic number.