Science : Ch 05 – Periodic of Classification of Elements

Element ‘X‘ is a non-metal as it forms acidic oxide. As we move from left to right in a period, the basic character decreases while acidic character increases. Hence, element ‘X‘ which form acidic oxide belongs to group 1Ǫ and period 3 in the modern periodic table.

Germanium element found a place in the periodic table later in the place of Eka–silicon in Mendeleev’s periodic table.

The elements of the 2nd period contain two shells: K and L shell. So, the outermost shell is L.

As we move from left to right in periodic table, metallic character decreases and non-metallic character increases. Here Na, Si, Cl, Mg, Al belong to same period.

Na and K are alkali metals, whereas Mg and Ca are alkaline earth metals. Alkali metals are more electropositive as compared to alkaline earth metals and can easily lose electrons. Out of Na and K, K will easily lose electrons because of its bigger size and less electronic attraction.

All these elements belong to the same period, in which non-metallic character increases from left to right.   Li, O, C, Be and F belong to the same period, i.e., 2nd period. In a period on moving from left to right, non-metallic character increases.