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(i) In Mendeleev's Periodic Table, the e...

(i) In Mendeleev's Periodic Table, the elements were arranged in the increasing order of atomic masses. However, cobalt with atomic mass of 58.93 a.m.u. was placed before nickel having an atomic mass of 58.71 a.m.u. Give reason for the same.
(ii) Write the formula of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.

Text Solution

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(i) It was because elements with similar properties were grouped together and increasing order of atomic mass could not be followed.
(ii) Germanium is Eka-silicon. The formula is `GeCl_(4)`. Gallium is Eka-aluminium. The formula is `GaCl_(3)`.
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