Question

discuss some major merits of the mendeleev periodic table

Answer 1

Merits of Mendeleeff's periodic table

--》Anomalous pairs : In Mendeleeff periodic table , there are some pairs of elements in which the elements with the higher atomic weight is placed before that of the lower atomic weight elements in order to maintain the similarity in chemical properties of the elements belonging to the same group

the pairs are Co 58.9 & Ni 58.6

Te 127.6. & I 126.9

Ar 39.94 & K 39.10

--》 position of hydrogen : position of hydrogen is not justified

--》position of isotopes : The isotopes of an element have different atomic weight. But there is no positions for the isotopes in Mendeleeff's periodic table

--》position of lanthanides and antibodies : Two sets of 14 elements each , which follow Lanthanum and Actinium in the order of atomic weight, have not been provided regular or separate places in the periodic table . They have just been put together along with Lanthanum and Actinium

--》positions of elements of VIII group : three triads of the transition elements are placed in group VIII of the periodic table. they should have been given separate positions