Question

The most common oxidation state of oxygen is $- 2$. This is best explained as due to
A. $2$ electrons in the outermost shell
B. $4$ electrons in the outermost shell
C. $6$ electrons in the outermost shell
D. $8$ electrons in the outermost shell

Answer 1

Oxidation state indicates the total number of electrons that an element gains or loses to obtain noble gas configuration and complete their octet. The oxidation state of an element is an integer value which may be positive, negative or zero. Oxidation has an electronic configuration of $1{s^2}2{s^2}2{p^4}$.

Complete step by step answer:
The oxidation state of an element is the measure of oxidation of an element. The oxidation state of an element is an integer value which may be positive, negative or zero. It indicates the total number of electrons that an element gains or loses to obtain noble gas configuration and complete their octet. Thus, if the element gains electrons to complete their octet then the oxidation state is signified by a negative charge and if it loses electrons then its oxidation state gains a positive charge.
The oxidation state of a free element is always equal to zero for a monatomic ion; it is equal to the charge of the ion. The sum of oxidation states of all the elements in a compound is equal to the charge on the whole compound.
Oxidation has an electronic configuration of $1{s^2}2{s^2}2{p^4}$ thus, oxygen atom has a total of $6$ electrons in its outermost shell and to complete its octet it requires $2$ electrons. So, it will have to gain $2$ electrons to obtain a noble gas configuration and its oxidation state will be equal to $- 2$. But in case of peroxide oxygen has an oxidation state of $- 1$.

Therefore, the correct option for the above question is option (C) $6$ electrons in the outermost shell.

Note:
As we know that oxygen is very important to sustain life, it exists as ${O_2}$ and is used for the production of plastics, steel and other metals and products. It is used for medical therapies and for life support systems in aircrafts, submarines and spaceflights.