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Ozone (O3) Lewis Structure - Steps of Drawing

Ozone (O3) Lewis Structure | Steps of Drawing

Ozone (O3) is an allotrope of oxygen and contains three oxygen atoms. In the lewis structure of ozone, there are one double bond and one single bond. Also, there are charges in two oxygen atoms in O3 lewis structure. Lewis structure of O3 can be drawn by starting from valence electrons of oxygen atoms in several steps. Each step of drawing the lewis structure of O3 is explained in detail in this tutorial. After drawing the lewis structure of NH3, you can decide shape of the O3 molecule.


O3 lewis structure

O3 lewis structure

In the lewis structure of NH3, you can see there are one double bond and one single bond between oxygen atoms. From three oxygen atoms one oxygen atom has one lone pair. Another one has two lone pairs and remaining one has three lone pairs. Also, one oxygen atom has a -1 charge and another oxygen atom has a +1 charge.




Steps of drawing lewis structure of O3

There are several steps to draw the lewis structure of O3. When you follow these steps properly, you can learn how to draw a lewis structure quickly and properly.

steps of drawing lewis structure of O3

  1. Determine total number of electrons of the valance shells of oxygen atoms
  2. Total electrons pairs existing as lone pairs and bonds
  3. Center atom selection and drawing the sketch
  4. Mark lone pairs on atoms
  5. Mark charges on atoms if there are charges on atoms.
  6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.

Important: Drawing the correct lewis structure is important to draw resonance structures correctly.



Total number of electrons of the valance shells of O3

There is only oxygen as an element in ozone. Oxygen belongs to the group VIA and contains six electrons in its last shell. Now we know how many electrons includes in valence shells of oxygen atom.


To find out total valence electrons given by a particular element, you should multiply number of electrons of the valance shell by the number of atoms of that element.


  • valence electrons given by oxygen atoms = 6 * 3 = 18

  • Total valence electrons = 18



Total valence electrons pairs in ozone

Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells

Total electron pairs are determined by dividing the number total valence electrons by two. For, O3, Total pairs of electrons are 9.



Sketch and selection of center atom of O3 molecule

Because there is only oxygen as an element, no need to worry about selecting the center atom. Therefore we can draw the sketch of O3

sketch of O3

Lone pairs on atoms

After determining the center atom and sketch of O3 molecule, we can start to mark lone pairs on atoms. Remember that, there are total of nine electron pairs.

  • There are already two O-O bonds in the above drawn sketch. Therefore, there are only seven (9-2) electron pairs remains to mark on atoms.
  • Usually, those remaining electron pairs should be started to mark on outside atoms. Also, remember that oxygen atom cannot keep more than eight electrons in its las shell. Considering these facts, we can mark electron pairs on oxygen atoms.
  • In this step, One oxygen will keep three lone pairs while and other two oxygen atoms will keep two lone pairs. So, all remaining lone pairs are now marked.
mark lone pairs on oxygen atoms in ozone

Mark charges on atoms and check octal rule

If there are charges on atoms in the above structure, they should be marked as the next step. Yes, there are charges on two oxygen atoms as the below figure. Determining the charges is important to find the best lewis structure. That's why we are trying to find charges.

Also, we can see one oxygen has only six electrons in its last shell. Therefore, this structure is not stable and impossible. in the next step, we will correct it.

mark charges on atoms in O3 lewis structure as a step

Check the stability and minimize charges on atoms by converting lone pairs to bonds

Because one oxygen has only six electrons, we convert a lone pair on center oxygen atom to make a bond with that oxygen atom as in the following figure.

convert lone pair to bond to obtain to most stable lewis structure of ozone O3

Now, you can see, every oxygen atom has eight electrons in their valence shells. Therefore, this structure is much stable than previous structure. But, we cannot convert more lone pair to bonds. So, this structure is the best lewis structure of O3.



Questions


the total number of valence electrons in ozone (o3) is

A oxygen atom has six electron in its valence shell. In O3 molecule, there are three oxygen atoms. Therefore, there are total of 18 valence electrons in ozone molecule.

















Lewis Structures of Molecules



Chemical Reactions