Senin, 19 November 2012

Dot Structure|How do I draw a Lewis Structure for a molecule– #35



How do I draw the Lewis electron dot structure of cyanamide  CN2H2? 
A simple and general procedure for writing Lewis structures is given in a previous article entitled “Lewis Structures and the Octet Rule”. Relevant worked examples were given in the following articles: Examples #1, #2, #3 , #4, #5, #6,  #7#8, #9, #10, #11, #12, #13, #14 #15, #16, #17, #18, #19, #20, #21, #22,  #23,  #24, #25, #26, #27, #28, #29, #30, #31, #32, #33 and #34.

Let us consider the case of  cyanamide  CN2H2.   

Step 1: Connect the atoms with single bonds. 

What is the Lewis structure of cyanamide CN2H2

Fig. 1: Connect the atoms of the CN2H2 molecule with single bonds.
 Step 2: Calculate the # of electrons in π bonds (multiple bonds) using  formula (1)


Where n in this case is 3 since CN2H2 has 3 non-hydrogen atoms.
Where V = 5*2 + 4 + 1*2 = 16
Therefore, P = 6n + 2 – V = 6 *3 + 2 – 16 = 4   So  there are either 2 double bonds or 1 triple  bond.
  
Step 3 & 4: The Lewis dot structures of  CN2H2  areas follows:
What is the Lewis structure of cyanamide CN2H2

Fig. 2: Lewis electron dot structures of the cyanamide CN2H2.
  
 Lewis electron dot  Structure #1 is the major contributor to the hybrid because it is more stable than #2 (octet of electrons around each atom and no charge sepatation).

Tidak ada komentar:

Posting Komentar