Write the formulae of chlorides of Eka-silicon and Eka-aluminium,the elements predicted by Mendeleev.

(A) Mendeleev predicted the existence of several elements that were not discovered at that time.
He named the element below silicon as Eka-silicon,which was later identified as Germanium $(Ge)$. Since silicon is in group $14$,its chloride is $SiCl_4$. Therefore,the formula for the chloride of Eka-silicon is $GeCl_4$.
He named the element below aluminium as Eka-aluminium,which was later identified as Gallium $(Ga)$. Since aluminium is in group $13$,its chloride is $AlCl_3$. Therefore,the formula for the chloride of Eka-aluminium is $GaCl_3$.
Thus,the formulae are $GeCl_4$ and $GaCl_3$.