Electrons In Oxygen

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So if your calculating the total amount of protons, neutrons & electrons in both atoms you simply times it by two in one atom of oxygen there is 8 protons, electrons & neutrons so in both of them. Oxygen has eight total electrons — two orbit the nucleus in the atom's inner shell and six orbit in the outermost shell. The outermost shell can hold a total of eight electrons, which explains.

Lewis structure of NO2 (Nitrogen dioxide) is drawn in this tutorial step by step. You can learn basics of how to draw a lewis structure properly from this example.


This is a special case of lewis structure drawing because, there is a unpaired electron on nitrogen atom. You will see this case when we draw the lewis structure of NO2 in next sections of this tutorial.


Steps of drawing NO2 lewis structure

Following steps are required to draw the NO2 lewis structure and they are explained in detail in this tutorial.

  1. Find total number of electrons of the valance shells of nitrogen and oxygen atoms
  2. Total electrons pairs
  3. Center atom selection
  4. Put lone pairs on atoms
  5. Check the stability and minimize charges on atoms by converting lone pairs to bonds.

Drawing correct lewis structure is important to draw resonance structures.


Total number of electrons of the valance shells of nitrogen and oxygen atoms

Nitrogen and oxygen are located at VA and VIA groups respectively in the periodic table. So nitrogen has five electrons in its valence shell. In oxygen atom, there are six electrons in its valence shell.


  • Total valence electrons given by nitrogen atom = 5

There are two oxygen atoms in NO2, Therefore

  • Total valence electrons given by oxygen atoms = 6 *2 = 12

  • Total valence electrons = 5 + 12 = 17

Total valence electrons pairs

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, NO2, Total pairs of electrons are 8 and one electron exists as unpaired electron because 17 cannot be divided exactly by 2.


Center atom of NO2

To be the center atom, ability of having greater valance is important. Therefore nitrogen has the more chance to be the center atom (See the figure). So, now we can build a sketch of NO2.


Lone pairs on atoms

There are already two N-O bonds in the sketch. Therefore only six valence electrons pairs are remaining.

Mark those six valence electrons pairs as lone pairs in outside atoms (on oxygen atoms). One oxygen atom will take three lone pairs following the octal rule (oxygen and nitrogen atoms cannot keep more than eight electrons in their valence shells).

Mark unpaired electron on nitrogen atom.


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

Electrons In Oxygen 8

The drawn structure is not a stable one because both oxygen atoms and nitrogen atoms have charges. Also nitrogen has a +2 charge and it decreases the stability of that structure.

Now, we should try to minimize charges by converting lone pair(s) which exist on oxygen atoms to bonds. So convert one lone pair of one oxygen atom to a N-H bond.

Now there is a double bond between nitrogen and one oxygen atom. There is a single bond also with nitrogen atom and other oxygen atom.


In new structure, charges of atoms reduced than previous structure. Now there is no any charge on one oxygen atom. Charge of nitrogen atom is also decreased to +1 from +2. Now you understand this structure of NO2 is more stable than previous structure. So, this structure has more chance to be the lewis structure of NO2.


We cannot convert more lone pairs of other oxygen atom to make a bond with nitrogen atom because a nitrogen atom cannot keep more than eight electrons in its valence shell.



NO2 structure

The bond length between the nitrogen atom and the oxygen atom is 119.7 pm. That means both bonds exist between oxygen and nitrogen are same.

Due to exist of unpaired electron, NO2 is a free radical.


There is a unpaired electron on nitrogen atom in NO2 lewis structure. Cannot it be shifted to an oxygen atom?

In above lewis structure, octal of oxygen atoms are already completed. There is no chance to have more than eight electrons in last shell.


Effect of unpaired electron

NO2 is a free radical. When it is in the presence of sun light, reacts with oxygen gas and produce NO and atomic oxygen. This is an initial step of photochemical smog which is occurred at cities which have high traffics.


Oxidation number of NO2

Oxygen is more electronegative than nitrogen. Therefore electrons of bonds are attracted towards oxygen atoms more than nitrogen.


Oxygen

There are three bonds between (two σ + one π) nitrogen atom and oxygen atoms. De to those bonds, nitrogen partially loses its three electron. So due to that case, nitrogen gets +3 oxidation state. But, wait. When your consider last shell of nitrogen atom, nitrogen belongs only four electrons. So nitrogen atom is lacking one electron and it makes +1 oxidation number. At finally, overall oxidation number of nitrogen is +4 (+3 + 1).


Questions

Ask your chemistry questions and find the answers

number of π bond pairs in no2

There is only one π bond in NO2 lewis structure.


What is the colour of NO2? I have heard that it is brown colour. Is it true. Why NO2 has a colour?

At room temperature, nitrogen dioxide is a brown colour gas. In lewis structure of NO2, there is a unpaired electron on nitrogen atom. That unpaired electron is the reason for showing colours by NO2 molecule.

Electrons In Oxygen 16


NO2 structure?

There is an unpaired electron on nitrogen atom. Therefore the molecule has three electron pairs around nitrogen atom and is trigonal planar for electron pair geometry. The one lone electron exerts a less repulsion than normal on the two bonding oxygen atoms so they are able to spread out more to a 1340 bond angle from the ideal of 1200.


What is the difference of lewis structures of NO2 and NO2-

In the lewis structure of NO2, there is a unpaired electrons on nitrogen atom. But in the NO2- lewis structure, there is lone pair on nitrogen atom.



Determine oxidation number of nitrogen in NO2NO2- lewis structureN2O lewis structure, resonance structures N2O5 resonance structuresResonance structures examples Nitrogen dioxide acidity


Related lewis structures

P2O5 lewis structureOH- lewis structureAmmonium ion (NH4+) lewis structureH2CO3 lewis structure

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


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.


  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.


Electrons In Oxygen 17

  • 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


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 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.


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.


Electrons In Oxygen Atom

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.



Testing ammonia gas Sodium and ammonia reaction Ammonia and chlorine reactionNO2 lewis structure