write note on position of isotopes in the mendeleev's and the modern periodic table
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Let us first understand the basis on which the Mendeleev and Modern Periodic Tables were formed.
The Mendeleev Periodic Table was based on the Mendeleev Periodic Law, which stated that "All the physical and chemical properties of elements are the periodic functions of their atomic weight".
However, the Modern Periodic Table was based on the Modern Periodic Law, which stated that "All the physical and chemical properties of elements are the periodic functions of their atomic number".
Isotopes are elements with same atomic number but different atomic weights. Hence, each isotope needed to be given a separate place in Mendeleev's periodic table as they had different atomic weights. However, there was no provision for isotopes in this periodic table. This was one of the major drawbacks of Mendeleev's periodic table, and one of the prime reasons for it to be replaced by the modern periodic table in the future.
However, when coming to the Modern Periodic Table, we notice that it has been constructed based on the atomic number and not atomic weights. Since isotopes are having same atomic number but different atomic weights, they are not given any special place in the Modern Periodic Table, as the Modern Periodic Table doesn't take atomic weights into consideration.
To summarize, isotopes had to be given different positions in Mendeleev's periodic table due to their differing atomic weights. However, this was not the case. In the Modern Periodic Table, atomic weight had no scope in deciding position of elements and thus isotopes are not considered for separate places.
The Mendeleev Periodic Table was based on the Mendeleev Periodic Law, which stated that "All the physical and chemical properties of elements are the periodic functions of their atomic weight".
However, the Modern Periodic Table was based on the Modern Periodic Law, which stated that "All the physical and chemical properties of elements are the periodic functions of their atomic number".
Isotopes are elements with same atomic number but different atomic weights. Hence, each isotope needed to be given a separate place in Mendeleev's periodic table as they had different atomic weights. However, there was no provision for isotopes in this periodic table. This was one of the major drawbacks of Mendeleev's periodic table, and one of the prime reasons for it to be replaced by the modern periodic table in the future.
However, when coming to the Modern Periodic Table, we notice that it has been constructed based on the atomic number and not atomic weights. Since isotopes are having same atomic number but different atomic weights, they are not given any special place in the Modern Periodic Table, as the Modern Periodic Table doesn't take atomic weights into consideration.
To summarize, isotopes had to be given different positions in Mendeleev's periodic table due to their differing atomic weights. However, this was not the case. In the Modern Periodic Table, atomic weight had no scope in deciding position of elements and thus isotopes are not considered for separate places.
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