(a) Mendeleev arranged elements in the ascending order of their atomic masses. There was no fixed position for hydrogen in his periodic table, as it resembled alkali metals as well as halogens. (b) Elements of higher atomic mass were placed before elements of lower atomic mass. Cobalt with atomic mass 58.93 was placed before nickel with atomic mass 58.71. (c) Elements having different properties were placed in the same sub group like manganese (Mn) was placed with halogens which had totally different properties to know more please watch videos in the link given below

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Mendeleev arranged elements in the ascending order of their atomic masses. There was no fixed position for hydrogen in his periodic table, as it resembled alkali metals as well as halogens. (b) Elements of higher atomic mass were... https://gurushala.co/search?keyword=mendeleev

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Demerits of Mendeleev Periodic Table He was unable to locate hydrogen in the periodic table. Increase in atomic mass was not regular while moving from one element to another. ... Later on, isotopes of elements were found which violated Mendeleev's periodic law.

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