Question

table Position of isotopes in the Mendeleev's and the modern periodic table​

Answer 1

Answer:

Isotopes :-

Isotopes have the same atomic number, similar chemical properties but different atomic masses. Based on the periodic law, an isotope is an element, which must have a separate place in the periodic table. However, there are no places for isotopes in his periodic table.

Answer 2

Explanation:

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1. Isotopes were discovered long time after Mendeleev developed the periodic table. All isotopes of the same element have different atomic masses but same atomic number. They have similar chemical properties.

2. As isotopes have the same chemical properties but different atomic masses, a challenge was posed in placing them in Mendeleev’s periodic table.

3. In Mendeleev’s periodic table, elements are arranged in increasing order of their atomic masses such that chemically similar elements are placed together in a group.

4. So, it became difficult to place isotopes in Mendeleev’s periodic table. Therefore, isotopes were not given separate place in Mendeleev’s periodic table.

5. In Modern periodic table, elements are arranged in increasing order of their atomic number. Hence, all the isotopes of an elements occupy the same position in the modern periodic table.

• ⇒ Thus, the isotopes of element are placed in the same place of that of the element instead of been given different place in modern periodic table for each isotope.