Method for Lewis dot structures: The nitrate ion #56

A simple procedure for writing Lewis Dot Structures was given in a previous article entitled “Lewis Structures and the Octet Rule”. 

Several worked examples relevant to this procedure were given in previous posts please see the Sitemap - Table of Contents (Lewis Electron Dot Structures).

Let us consider the case of the nitrate ion. The molecular formula is NO₃^-.

 

Step 1: Connect the atoms with single bonds

Fig. 1 : Connect the atoms of NO₃^-with single bonds

Step 2:  Calculate the # of electrons in π bonds (multiple bonds) using  formula (1):

Where n in this case is 4. Where V = (5 +6*3) – (-1) = 24 , V is the number of valence electrons of the nitrate ion.

Therefore, P = 6n + 2 – V = 6 * 4 + 2 – 24  = 2     So, there is 1 double bond.

Step 3 & 4: The  dot resonance structures of  NO₃^-  areas follows:

Fig. 2 : Plausible Lewis Resonance Dot Structures of NO₃^-   

Therefore, there are 3 possible Lewis resonance structures for NO₃^-