Question

What is the charge of $O_2$ ?

Answer 1

Hint :When we are just talking about the element, then using the symbol is pretty self-explanatory. But sometimes we need to describe how the element appears in the word or in chemicals which may be different from its elemental form.

Complete Step By Step Answer:
When we are just talking about the element, then using the symbol is pretty self-explanatory. But sometimes we need to describe how the element appears in the word. Oxygen atom contains a total number of eight electrons out of which only six of these are in the outermost shell or orbital and the electronic configuration of an oxygen atom is $1s^{2}2s^{2}2p^4$ .
Elements always prefer to have their outer shells completely filled and obtain noble gas configuration and they want this state as easily as possible. In the case of Oxygen, it is easier to gain two electrons rather than losing six electrons.
Also dioxygen gas, $O_2$ the stuff we are breathing now is Neutral; Oxygen can form oxides upon reduction.
 ${\displaystyle \frac{1}{2}}{O_2}_{(g)}+2e^{-}\to O^{2-}$ and since oxygen is a powerful oxidant this reaction is facile. On the other hand, we could form peroxides i.e. salts of where each oxygen atom is associated with nine electrons rather than eight.
 $O_{2(g)}+2e^{-}\to {}^{-}O-O^{-},$ i.e. ${}^{-}O-O^{-}\equiv O_2^{2-}$

Note :
Molecular oxygen ( $O_2$ ) is composed of two oxygen atoms bound to each other via covalent chemical bonding which makes it a diatomic molecule. Atomic oxygen has a total of eight electrons. Therefore, we write the two as a subscript of Oxygen, indicating two molecules of oxygen.