Question

What is the covalency of ${{O}_{2}}\text{ and }{{N}_{2}}$ molecule?
a.) 0,0
b.) 1,2
c.) 2,3
d.) 3,3

Answer 1

Hint: To calculate the covalency we have to calculate the number of electrons shared with other atoms during the formation of chemical bond. A chemical bond is a type of bond which is a lasting interaction between the atoms or ions or molecules which leads to the formation of chemical compounds.

Complete step by step answer:
The covalency of any atom is calculated by the number of atoms shared with other atoms during the formation of chemical bonds with other atoms.
If we talk about molecule of oxygen “O”
Atomic number of oxygen = 8
Number of valence electrons in oxygen which means the electrons present in the last shell of oxygen = 6
Oxygen requires 2 more electrons to complete its octet or to acquire the noble gas electronic configuration.

In oxygen molecule ${{O}_{2}}$ ,
Oxygen forms a double bond with other oxygen to complete its octet or to acquire the noble gas electronic configuration.
Number of shared electrons in an oxygen molecule is 2 hence its covalency is 2.
Similarly, If we talk about molecule of Nitrogen “N”
Atomic number of nitrogen = 7
Number of valence electrons in oxygen which means the electrons present in the last shell of oxygen = 5
Nitrogen requires 3 more electrons to complete its octet or to acquire the noble gas electronic configuration.

In nitrogen molecule ${{N}_{2}}$ ,
Nitrogen forms a triple bond with other nitrogen to complete its octet or to acquire the noble gas electronic configuration.
Number of shared electrons in a nitrogen molecule is 3 hence its covalency is 3.
Hence the covalency of molecules or nitrogen and oxygen is 3 and 2 respectively.
So, the correct answer is “Option C”.

Note: Write the correct valence electrons for the given molecule as it plays the major role in determining the covalency of the molecule. The coordinate covalent bonds are also counted in finding the covalency of a molecule.