Question

Select the member(s) of group $14$ that
(i) forms the most acidic dioxide
(ii) is commonly found in $+2$ oxidation state
(iii) is used as semiconductor.

Answer 1

(i) Forms the most acidic dioxide

Element which forms most acidic oxide (Group 14):

Oxides of non-metals are acidic in nature. Down the group, non-metallic character decreases and hence acidic nature of oxides decreases.

Carbon is the most non-metallic element of group $14$ and hence its dioxide is most acidic.

Additional Information:

The dioxides $C{O}_2$ , $Si{O}_2$ and $Ge{O}_2$ are acidic, whereas $Sn{O}_2$ and $Pb{O}_2$ are amphoteric in nature.

Final answer: Carbon


(ii) Element is commonly found in $+2$ oxidation state

Inert pair effect:

The inert pair effect is tendency of two electrons in the outermost atomic sorbital to remain unshared in compounds of post-transition metals. In lead $\left(Pb\right)$ inert pair effect is most prominent because as we move down the group from carbon to lead the tendency of non-participation inner ns electrons in chemical bonding increases due to the large size of atoms. So $Pb$ is having more tendency of showing an inert pair effect.

Element commonly found in $+2$ oxidation state (Group $14$):

As the inert pair effect becomes more predominant down the group, so stability of $+2$ oxidation state increases down the group. This is why lead is commonly found in $+2$ oxidation state.

Final answer: Lead


(iii) Element is used as semiconductor.

In group $14$, elements silicon and germanium are neither too electronegative nor too electropositive, so they act as metalloids and behave as semiconductors.

Final answer: Silicon and Germanium