Question

what are the limitations of Mendeleev's periodic table and explain

Answer 1

Answer:

Mendeleev could not determine the accurate position of the hydrogen atom in his table.

This is because hydrogen’s characteristics are very similar to halogens and alkali metals.

Other key limitations in Mendeleev periodic table were that the atomic number in the table was not shown increasing in a regular pattern and the symmetry of the table was also disturbed.

Explanation:

Answer 2

$\large{\underline{\underline{\red{\sf{\dag Mendeleev's\: Periodic\:Table:- }}}}}$

$\bullet$ According to Mendeleev the properties of elements were related to their atomic weights.on that basis is formulated the periodic table.

$\bullet$Mendeleev's periodic law states that the physical and chemical properties of the element of the periodic functions of their atomic weights.

$\bullet$He compiled a periodic table by arranging the 63 elements known them in 8 vertical columns for groups and 7 horizontal rows known as periods.

$\bullet$Later when the noble gases were discovered mendeleef give a modified periodic table by including the noble gases in the zero group.

$\bullet$ The group's range from 0 to 8 and this except the zero and the eight group was further subdivided into two groups A and N in number the products from 1 to 7 of which the seventh period is incomplete .

${\underline{\underline{\purple{\tt{\leadsto Limitations\;of\:Mendeleev's\: Periodic\:Table:- }}}}}$

$\bullet$In certain parts of the periodic table elements with the highest atomic weight were placed before that of atomic weight in order to maintain the gradation in properties these are known as anomalous pairs . Here are the examples:

$\boxed{\begin{tabular}{|c|c|c|c|c|c|} \cline{1-6} \multicolumn{2}{|c|}{Example 1} & \multicolumn{2}{|c|}{Example 2}&\multicolumn{2}{|c|}{Example 3} \\ \cline{1-6} (i)Co(Cobalt) & Ni(Nickel) & (ii)Te(Tellurium) & I(Iodine) & (iii)Ar(Argon) & K(Potassium) \\ \cline{1-6} 58.9&58.6&127.6&126.9&39.94&39.10 \\ \cline{1-6} \end{tabular}}$

$\bullet$Isotopes of an element have different atomic weights however there is no position for the isotopes in the Mendeleev's periodic table.

$\bullet$ Three groups of transition elements are placed in the group VIII of the periodic table .They should have been given a separate positions.

$\bullet$Transition elements were placed with other elements under the same group.

$\bullet$ Coinage coinage metals were placed along with alkali metals.