Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.
(a) Name the elements which have taken the place of these elements
Ans. Eka-silicon was replaced by Germanium and Eka-aluminium was replaced by Gallium.
(b) Mention the group and the period of these elements in the Modern Periodic Table.
Ans. Gallium: Group 13 Period 5
Germanium: Group 14 period 5
(c) Classify these elements as metals, non-metals or metalloids
Ans. Gallium is metal, while Germanium is metalloid
(d) How many valence electrons are present in each one of them?
Ans. Gallium has 4 valence electrons, while Germanium has 5.
