Nitrogen Valence Electrons

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Transition Metals: Groups 3-12 - d and f block metals have 2 valence electrons; Boron Group or Earth Metals: Group 13 (IIIA) - 3 valence electrons; Carbon Group or Tetrels: - Group 14 (IVA) - 4 valence electrons; Nitrogen Group or Pnictogens: - Group 15 (VA) - 5 valence electrons; Oxygen Group or Chalcogens: - Group 16 (VIA) - 6 valence electrons. NF 3 (Nitrogen trifluoride) is very similar to the NCl 3 and NH 3 Lewis structure. In the NF 3 Lewis structure (and all structures) hydrogen goes on the outside. Hydrogen only needs two valence electrons to have a full outer shell. In the Lewis structure for NF 3 there are a total of 8 valence electrons.


Nitrogen

Lewis structure of NO3- ion is drawn step by step in this tutorial. Total valence electrons of nitrogen and oxygen atoms and negative charge are considered to draw the NO3- lewis structure. You will every fact of drawing lewis structures from this tutorial which will help you to draw more lewis structures in the future.


Lewis Structure of nitrite ion

Nitrogen Valence Electrons And Covalent Bonds


Now, we are going to learn, how to draw this lewis structure of NO3- ion.


Steps of drawing NO3- lewis structure

Following steps are required to draw NO3- 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 and including charge of the anion
  2. Total electrons pairs in valence shells
  3. Center atom selection from nitrogen and oxygen atom
  4. Put lone pairs on atoms
  5. Stability of lewis structure - Check the stability and minimize charges on atoms by converting lone pairs to bonds.

Drawing correct lewis structure is important to draw resonance structures. In another tutorial, we learn how to draw resonance structures of nitrate ion.


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

There are one nitrogen atom and three oxygen atoms in the nitrate ion. Also there is a -1 charge on the nitrate ion.

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 three oxygen atoms in NO3-, Therefore

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

Due to -1 charge, another electrons is added

  • Due to -1 charge, received electrons to valence electrons= 1

  • Total valence electrons = 5 + 18 + 1 = 24

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-, there are 24 valence electrons, so total pairs of electrons are 12.


Center atom of NO2-

To be the center atom, ability of having greater valance is important. Nitrogen can show valence,5. But, oxygen's maximum valence is 2. Therefore nitrogen has the more chance to be the center atom (See the figure). So, now we can build a sketch of NO3- ion.


Sketch of NO2- ion


Lone pairs on atoms

There are already three N-O bonds in the sketch. Therefore only nine valence electrons pairs are remaining to draw the rest of ion.

Start to mark those nine valence electrons pairs on outside atoms (oxygen atoms) as lone pairs. 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). All nine valence electrons pairs (9) are spent when lone pairs are marked on oxygen atoms.

Therefore, there is no ine valence electrons pairs to mark on nitrogen atom.


Check the stability of drawn NO2- ion and minimize charges on atoms by converting lone pairs to bonds

Check charges on atoms and mark them as below. Charges are important to decide the lewis structure of the ion.


The drawn structure for NO3- is not a stable structure because oxygen atoms and nitrogen atoms have charges. When a molecule or ion has so many charges on atoms, that structure is not stable.


Now, we should try to minimize charges by converting lone pair or pairs which exist on oxygen atoms to bonds. So we convert one lone pair of one oxygen atom as a N-O bond.


Now there is a double bond between nitrogen and one oxygen atom. There are also two single bonds (N-O) with nitrogen atom and other oxygen atoms.


In new structure, charges of atoms are reduced. Now there is no any charge on one oxygen atom. Also, charge of nitrogen atom is reduced from +2 to +1. Now you understand this structure of NO3- is more stable than previous structure due to less charges on atoms.


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



Questions


How many lone pairs are around the nitrogen atom in nitrate ion?

No electrons pairs exist on nitrogen atom. But, on nitrogen atom, there is a +1 charge. Around the nitrogen atom, there are two single bonds and double bond.


Related tutorials

NO2 lewis structureN2O lewis structure, resonance structures N2O5 resonance structuresResonance structures examples Nitrogen dioxide acidity


Hydrogen Cyanide is a colorless, flammable, and poisonous chemical liquid. Represented by the chemical formula, HCN is one of those molecules that has an interesting Lewis structure. This liquid is used in electroplating, mining, and as a precursor for several compounds.

And to further understand Hydrogen Cyanide’s physical properties, it is vital to know its Lewis structure and molecular geometry. Keep reading this post to find out its shape, polarity, and more. First, let us look at its Lewis dot structure and the valence electrons that participate in forming bonds.

HCN valence electrons

To draw the Lewis dot structure of any molecule, it is essential to know the total number of valence electrons in the structure. To know the valence electrons of HCN, let us go through the valence electrons of individual atoms in Hydrogen Cyanide.

This molecule is made up of three different atoms: Hydrogen, Carbon, and Nitrogen.

Hydrogen has one valence electron, and it only needs one more electron to complete its valence shell as it is an exception to the octet rule.

So Hydrogen has one valence electron.

Whereas Carbon has four valence electrons and Nitrogen has five valence electrons.

Total number of valence electrons in HCN= No. of valence electrons in Hydrogen + No. of valence electrons in Carbob+ No.of valence electrons in Nitrogen

= 1+4+5

= 10 valence electrons

Hence, Hydrogen Cyanide, HCN, has ten valence electrons.

HCN Lewis structure

Once you get the total number of valence electrons, you can make a Lewis dot structure of HCN. This structure helps in understanding the arrangement of valence electrons around the atoms in the molecule. It also aids with understanding the bonds formed in the molecule and the electrons not participating in any bond formation.

To start with making the Lewis Structure of HCN, we will first determine the central atom. And then place the remaining atoms in the structure.

As Carbon is the least electronegative atom in this molecule, it will take the central position. Place the Hydrogen and Nitrogen atoms on both terminal sides of the Carbon like this:

Once you have arranged the atoms, start placing the valence electrons around individual atoms. Like Hydrogen will have one electron, Carbon will have four electrons, and Nitrogen will have five electrons around its atom like this:

If you look at the structure closely, you will realize that Hydrogen can share one electron with the Carbon atom and become stable. So both Carbon and Hydrogen will share two electrons and form a single bond.

Nitrogen Valence Electrons Shell

H-C N

Now that we have completed the valence shell for Hydrogen let us do the same for the Carbon atom. The atom is left with only three valence electrons as it has shared one electron with Hydrogen. And so Carbon will share its remaining three electrons with Nitrogen to complete its octet, resulting in the formation of a triple bond between Carbon and Nitrogen.

Carbon has a complete octet by forming a single bond with Hydrogen and a triple bond with the Nitrogen atom. Similarly, Nitrogen has a complete octet as it only needed three electrons for completing the octet that it got by sharing the electrons with Carbon. Hydrogen has two electrons in its outer valence shell. The rest two electrons are nonbonding electrons.

HCN Molecular Geometry

The molecular Geometry of any given molecule helps understand its three-dimensional structure and the arrangement of atoms in a molecule, and its shape. Hydrogen Cyanide has geometry like AX2 molecule, where A is the central atom and X is the number of atoms bonded with the central atom.

As Carbon is bonded to two atoms, it follows the molecular geometry of AX2. And as per VSEPR theory, molecules covered under AX2 have a linear molecular geometry.

Hence Hydrogen Cyanide has linear molecular geometry.

HCN Bond Angles

Once we know the Lewis structure and Molecular Geometry of any molecule, it is easy to determine its bond angles and polarity. As this molecule has a linear molecular geometry, HCN has bond angles of 180 degrees.

HCN Shape

As both Hydrogen and Nitrogen are placed far from each other at bond angles of 180 degrees, it forms a linear shape.

HCN Polarity

HCN in a polar molecule, unlike the linear CO2. And here is why:

Nitrogen Valence Electrons

Carbon has an electronegativity of 2.5, Hydrogen’s electronegativity is 2.1, and Nitrogen has an electronegativity of 3.

Although Hydrogen is the least electronegative, it can never take a central position. And due to the difference in electronegativities between Carbon and Hydrogen, the vector represents charge will be drawn from Hydrogen to Carbon. Similarly, as Nitrogen is more electronegative than Carbon, the vector will be towards Nitrogen from Carbon.

Despite quite a small difference in Carbon and Nitrogen’s electronegativities, it is considered a slightly polar bond as Nitrogen will try to pull the electrons to itself. Due to such differences, Hydrogen will have slightly positive charges, and Nitrogen will have slightly negative charges as the vector goes from Hydrogen to Nitrogen.

Thus Nitrogen becomes a negative pole, and the Hydrogen atom becomes a positive pole, making the molecular polar. Any molecule that has a difference of electronegativities of any dipole moment is considered as polar.

Nitrogen Valence Electrons Number

Hence, Hydrogen Cyanide is a polar molecule.

Nitrogen Valence Electrons Count

Concluding Remarks

List Of Valence Electrons For Each Element

To summarize everything in this article, we can say that:

  • Carbon forms one single bond with the Hydrogen atom and forms a triple bond with the Nitrogen atom.
  • HCN has a total of 10 valence electrons.
  • It is covered under AX2 molecular geometry and has a linear shape.
  • The bond angles of HCN is 180 degrees.
  • Hydrogen Cyanide is a polar molecule.