Question

What charge do group IV A atoms have when they become ions?
A) Either +4 or -4 but they don’t usually become ions
B) +4.
C) -4
C) +3
D) -3

Answer 1

Hint: The carbon family elements constitute group IV A of the periodic table. Recall their valence electronic configuration. They generally have the tendency to form covalent compounds. Carbon of this group shows catenation property and covalency of four.

Complete Solution :
- Group IV A of the periodic table includes the elements carbon (C), silicon (Si), germanium (Ge), tin (Sn) and lead (Pb). The valence electronic configuration of these elements is $n{s}^{2}n{p}^2$. Thus, these group elements have four electrons in their outermost shell, so they can either gain four electrons or lose their four electrons to complete their octet. When these elements gain four electrons, they will acquire -4 charge and when they will lose four electrons, they will acquire +4 charge.
- To form ions or to do ionic bonding, group IV A elements have to lose or gain four electrons, but they cannot do so because it requires a lot of energy to gain or lose the four electrons. Thus, they usually do not form ions. Instead, these elements form covalent compounds. We are so much aware about the catenation property of carbon. The sum of first four ionization enthalpies is very high, thus compounds in +4 oxidation state are generally covalent in nature.
- Hence accordingly charge of group IV A atoms is either +4 or -4, but they usually do not form ions.
So, the correct answer is “Option A”.

Note: Down the group IV A, due to the inability of $n{s}^2$ electrons of valence shell to participate in bonding, heavier elements of the group also have a tendency to show +2 oxidation state. Carbon and silicon mostly show +4 oxidation states. Germanium forms stable compounds in +4 oxidation states and only few compounds in +2 oxidation states. Tin forms stable compounds in both +$ and +2 oxidation states.