Question

Write the limitations of Mendeleev periodic table.

Answer 1

Answer:

• No fixed position was given to hydrogen. "Hydrogen exists as diatomic molecule."

• Isotopes I discovered long after mandali had proposed his classification of element.

• "Isotopes of an element have similar chemical properties but different atomic mass."

• Another problem was that masses don't increase in a regular manner in going from one element to the next so it was not possible to predict how many elements could be discovered between two elements especially when we consider the heavier elements.

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Answer 2

Explanation:

ANSWER

LIMITATIONS OF Mendeleev's Periodic Table :

Position of Hydrogen => Position of hydrogen in the perodic table is Uncertain , Because hydrogen is placed in 1 A group with Alkali metals .

Position of isotopes => isotopes haven't been given separate place in perodic table .

Cause of periodicity => Mendeleev could not explain the cause of periodicity .

Separation of similar elements => some dissimilar elements have been placed together .

Elements with large differences in properties were included in the same group. for example, hard metals like copper and silver were included along with soft metals like sodium and potassium.

No proper position could be given to the element hydrogen. In the periodic table, the location of hydrogen is uncertain. It was put with alkali metals within 1A class, but certain hydrogen properties are close to those of halogens. So, it can also be put for halogens in the band.

The increasing order of atomic mass was not strictly followed throughout. For example in cobalt and nickel & Tellurium and Indium.

As isotopes are atoms of the same element having different atomic masses, they should have been given different positions while arranging them in the order of atomic mass. But this was not done.