Write limitations of Mendeleev periodic table
Answers
limitations of Mendeleev's periodic table---------'-
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1.Position of hydrogen--
According to mendeleev, elements are arranged in increasing order of atomic mass .So, position of hydrogen may be arranged with the 1st group element or with 17th group element.
2. Position of isotopes---
lsotopes of different elements have different atomic masses so they should place in periodic table more than 1 case but it is not possible.
3. Abnormal pair of elements----
Argon has atomic mass 40 but placed in periodic table before potassium which has atomic mass as 39, but mendeleev table is arranged according to increasing atomic mass, and the reason of this is not explained by Mendeleev .
4.Position of 4f and 5f---
position of 4f and 5f are not explained by Mendeleev table.
5. cause of periodicity--
by mrndeleev table periodicity of elements is does not explained.
Answer:
Mendeleev arranged 63 elements known at that time in the periodic table. ...
Limitations of mendeleev's classification :
(i) He could not assign a correct position of hydrogen in his periodic table, as the properties of hydrogen resembles both with alkali metals as well as with halogens.