Question

The number of unpaired electrons \[{{\rm{O}}_{\rm{2}}}\] molecule is
A) 0
B) 1
C) 2
D) 3

Answer 1

Hint: The electrons of an atom that does not participate in the bonding process are called unpaired electrons. These electrons are also named lone pair electrons. Here, to find out the unpaired electrons, we have to first know the valence electrons.

Complete Step by Step Answer:
Let's first discuss what the valence electron is. They are the electrons that reside in the outermost shell of the atom. They take part in bond formation.

Let's discuss how a molecule of oxygen forms. The count of valence electrons in the Oxygen atom is six. The oxygen molecule is formed due to the formation of the covalent bond between the two atoms by sharing electrons so that they attain stability by achieving noble gas configuration, that is, valence electrons of eight.

Image: Oxygen molecule

From the above diagram, it is clear that each oxygen atom shares two electrons with the other atoms to form the double covalent bond so that they achieve an octet. And each atom of oxygen has two lone pairs on it. And they are not involved in the formation of bonds. So, two lone pairs are present on the oxygen atom.
Hence, option C is right.

Note: It is to be noted that a covalent bond forms because of the sharing of electrons by the bonded atoms. If one electron is shared, the bond formed is a single bond. And the sharing of two electrons gives a double bond and the sharing of three electrons gives a triple bond.