Lewis Dot Structure of the sulfite ion SO3-2 - Electron Dot Structure

Lewis Dot Structure of the sulfite ion SO₃^-2

A simple method for writing Lewis Structures is 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 sulfite ion. The chemical formula is SO₃^-2 . 

What is the SO₃^-2 Lewis structure?

 

Step 1: Connect the atoms with single bonds. The central atom is the sulfur atom.

 

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

Where n in this case is 4 since SO₃^-2 consists of four atoms.

Where V = (6 + 6 + 6 + 6 ) – (-2) = 26 , V is the number of valence electrons of the ion.

Therefore, P = 6n + 2 – V = 6 * 4 + 2 – 26  = 0   There are no  π electrons in SO₃^-2

Therefore, the structure in Step 1 is a plausible Lewis structure of SO₃^-2.

Electrons are placed around each atom so that the octet rule is obeyed. Since S is a third row element can accommodate more than 8 valence electrons.

 

Step 3 & 4: The Lewis, resonance structures of SO₃^-2  are as follows:

 

 

Resonance Structures #1-#3 are more stable due to less charge separation - even though the S atom has more than 8 electrons (expanded octet) - comparing to Structure #4. Structure #4 is less stable because of larger charge separation.

 

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Relevant Posts - Relevant Videos

Lewis Structures|Octet Rule: A Simple Method to write Lewis Structures

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Dot Structure |How do I draw a Lewis Structure for a molecule - Lewis Structure of Cyanamide

 

 

 

 

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References

1. G.N. Lewis, J.A.C.S, 38, 762-785, (1916)
2.  E. C. McGoran, J. Chem. Educ., 68, 19-23 (1991)
3. A.B.P. Lever, J. Chem. Educ., 49, 819-821, (1972)

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Key Terms

Lewis structures, electron dot structures, Lewis structures of the sulfite ion SO₃^-2, electron dot structures of the sulfite ion SO3-2, method for drawing Lewis structures,, chemistry, Chemistry Net

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Lewis Electron-Dot Structure for Chlorine Dioxide Ion (ClO2+)

Simple method for writing Lewis Dot Structures

of chlorine dioxide cation (ClO₂)⁺

A simple procedure for writing Lewis electron dot structures is 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).

Another example  for writing Lewis structures following the above procedure is given below.

Let us consider the case of the Lewis dot structures of chlorine dioxide cation (ClO₂)⁺.

How can we draw the Lewis structures of (ClO₂)⁺?

 

Step 1: Connect the atoms with single bonds. Chlorine is the central atom.

 

Step 2: Calculate the # of electrons in π bonds (multiple bonds) using  formula (1) in the article entitled “Lewis Structures and the Octet Rule”. 

Where n in this case is 3 since (ClO₂)⁺ consists of three atoms.

Where V = (7 + 6 + 6 ) – 1 = 18  

Therefore, P = 6n + 2 – V = 6 * 3 + 2 – 18 = 2

So, there are 2 π electrons (pi electrons) in (ClO₂)⁺ and the structure in Step 1 has 1 double bond. 

So the structure of Step 1 is the Lewis structure.

Electrons are placed around each atom so that the octet rule is obeyed. Since Cl is a third row element can accommodate more than 8 electrons.

Step 3 & 4: The Lewis resonance structures of  ClO₂⁺   are as follows:

Valence Electrons and Lewis Dot Structures – HNCS

Valence Electrons and Lewis Dot Structures – Isothiocyanic acid (HNCS)

A simple method for writing Lewis Dot Structures is 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 now the case of  isothiocyanic acid  (HNCS). How can we write a draw of the Lewis structures?         

 

Step 1: Connect the atoms with single bonds.

 

Fig.1: Connect the atoms of isothiocyanic acid (HNCS) 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 isothiocyanic acid has one hydrogen atom.

Where V = 1*1 + 1*5 + 1*4 + 1*6 = 16, V is the number of valence electrons of the atom.

Therefore, P = 6n + 2 – V = 6 *3 + 2 – 16 = 4   Therefore,  there are 2 double bonds or a triple bond.

 

Step 3 & 4: The Lewis resonance structures of  HNCS  are as follows:

 Fig.2 : Electron dot structures of isothiocyanic acid (HNCS)

Structure #3 is the most stable resonance Lewis structure since there is an octet of electrons around each atom and there is no charge separation. Structure #1 is more stable than Structure #2 since the negative charge is on N (3.04) which is more electronegative than S (2.58)

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Relevant Posts

Lewis Structure of Thiocyanate (SCN-)

Canonical Structures - Lewis Dot Structure of OCN-

Simple Procedure for writing the Lewis structures of CN+

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References

1. G.N. Lewis, J.A.C.S, 38, 762-785, (1916)
2.  E. C. McGoran, J. Chem. Educ., 68, 19-23 (1991)
3. A.B.P. Lever, J. Chem. Educ., 49, 819-821, (1972)

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Key Terms

lewis structures, simple method for writing Lewis structures, valence electrons, single bonds, electrons in π bonds, resonance structures

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Rules for writing Lewis electron resonance structures– Formamidine

A simple and automatic method for writing Lewis Dot Structures is given in a previous post 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 Lewis Dot Structures of formamidine HNCHNH₂

Step 1:  Connect the atoms 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 formamidine has 3 non-hydrogen atoms.

Where V = 1*1 + 1*5 + 1*4 + 1*1 +1*5 +1*1 +1*1 = 18, V is the number of valence electrons of the atom.

Therefore, P = 6n + 2 – V = 6 *3 + 2 – 18 = 2   there is 1 double bond.

The Lewis electron resonance structures of  formamidine  are as follows:

Structure #1 is the most stable electron dot structure because there is an octet of electrons around each atom and there is no charge separation.

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Lewis Structures and the Octet Rule - A simple method to write Lewis Structures

Simple Method for writing the Lewis Structures of carbon disulfide CS₂

 

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References

1. G.N. Lewis, J.A.C.S, 38, 762-785, (1916)
2. E. C. McGoran, J. Chem. Educ., 68, 19-23 (1991)
3. A.B.P. Lever, J. Chem. Educ., 49, 819-821, (1972)

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