Question

Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka $-$ silicon and Eka $-$ Aluminium.

Mention the group of these elements in the Modern Periodic Table :

• A. Group 12 and Group 13.
• B. Group 14 and Group 15.
• C. Group 14 and Group 13.
• D. Group 15 and Group 13.

Answer 1

Answer: (C)

Group 14 and Group 13.

Eka silicon means germanium. It occurred because of silicon whereas Eka aluminium occurred because of aluminium and later named it as gallium.

While filling the elements considering atomic number would be main and fundamental property there were gaps in the mentioned groups .

Hence, he filled them with these names.

Ga - $Ar3d^{10}4s^{2}4p^1$. Group number 13 as three valence electrons where as period 4 as outer most shell is 4.

Ge - $Ar3d^{10}4s^{2}4p^2$. Group number 14 as 4 valence electrons where as period 4 as outer most shell is 4.

Hence the correct option is C.