Question

state merits of mendeelevs periodic table

Answer 1

He predict the property of New elements
He left blank places which help scientists to discover new elements

Answer 2

$\huge {\rm {\underline {\underline{ \pink{Answer : - }}}}}$

$\large \sf(i) {\underline {\blue{Mendeleev's \: periodic \: law : - }}}$

" The physical and chemical properties of elements are the periodic functions of their atomic weights"

$\large \sf(ii) {\underline {\orange{Merits \: of \: Mendeleev's \: periodic \: table : - }}}$

◉ Elements with similar properties were kept under vertical coloumns called groups

◉ He predicted the properties and arrangement of elements which were not discovered too

EXAMPLES :- Scandium , Gallium , Germanium , Technetium

◉ He corrected the atomic weights of elements like Berylium , Indium , osmium and gold using empirical formula

$\large \sf(iii) \: {\underline {\green{Demerits \: of \: Mendeleev's \: periodic \: table : - }}}$

◉ Position of Hydrogen was not justified

◉ Position of isotopes were not given

◉ Order of increasing elements was not strictly followed

EXAMPLES :- Ar , K ; Co , Ni ; Te , I