7 Steps on N(ch3)3 Lewis Structure, Hybridization( Solved !)

Trimethylamine (N(CH3)3) has a nitrogen (N) atom with five valence electrons, each bonded to a methyl group (CH3) with one valence electron from carbon (C). The Lewis structure shows three single N-C bonds and a lone pair on nitrogen, totaling 8 electrons around N. The molecular geometry is trigonal pyramidal with bond angles slightly less than 109.5° due to lone pair-bond pair repulsion. The molecule is polar, influenced by the lone pair on nitrogen and the arrangement of methyl groups. The electronegativity of N (3.04) relative to C (2.55) also contributes to its reactivity and interactions.

The present article contains detail information of N(CH3)3 Lewis Structure. N(CH3)3 exists as a gas at room temperature. It is an organic compound which possess a fish-like odor.

The Lewis structure of N(CH3)3 consists of central atom nitrogen and three methyl groups surrounding the central atom. There is a lone pair on central atom nitrogen in the Lewis structure of Trimethylamine.

N(ch3)3 Lewis Structure
N(ch3)3 Lewis Structure

                                   

Molecular formula N(CH3)3 or C3H9N
Chemical Name Trimethylamine
N,N-Dimethylmethanamine
Lone pairs on the central atom 1
Number of valence electrons in N(Ch3)3 26
Molecular Geometry of N(CH3)3 Trigonal pyramidal
Electron Geometry of N(CH3)3 Tetrahedral
Bond Angle C-N-C 108 degrees
Resonance Effect Do not show resonance
Octet Rule Follows the octet Rule
Formal charge 0
Hybridisation of the central atom Sp3
Polar or non-polar Polar
Solubility in water Soluble in water
Acidic or basic Basic
symmetric Or Asymmetric Asymmetric
Characteristics of N(CH3)3
n(ch3)3 lewis structure
Lewis Structure of N(CH3)3

                 

Valence electrons in N(CH3)3 Lewis structure

In the Lewis structure of Trimethylamine the central Nitrogen atom, Carbon and the hydrogen atom has 5,4 and 1 electron respectively.

Types of atoms Valence electrons Number of atoms Valence electrons in N(CH3)3
Nitrogen 5 1 5*1 = 5
Carbon 4 3 4*3 = 12
Hydrogen 9 1 9*1 = 9
                26
Valence Electrons in Lewis structure of N(CH3)3

so, the number of valence electrons in Lewis N(CH3)3 is 26

How to draw N(CH3)3 Lewis structure?

Lewis structures are the drawings which show the patterns of bonding in the compound. These structures show the number of bonding and also the number of non-bonding electrons present in the compound.

Lewis structure of N(CH3)3 can be drawn in the following steps –

Step 1: Calculate the number of valence electrons

Valence electrons in central atom nitrogen, carbon and hydrogen are 5,4 and 1 respectively.

Types of atoms Valence ele ctrons Number of atoms Valence electrons in N(CH3)3
Nitrogen 5 1 5*1 = 5
Carbon 4 3 4*3 = 12
Hydrogen 9 1 9*1 = 9
                26
Valence Electrons in Lewis structure of N(CH3)3

So, the number of valence electrons in Trimethylamine is 26.

Step 2: Find out the central atom

Central atom in the Lewis structure.is usually the atom which has lowest subscript in the compound so Nitrogen is the central atom in N(CH3)3.

The skeletal structure of N(CH3)3 is –

image 113
Skeletal structure of N(CH3)3

                            

Step 3: Place a bond or a electron pair between Nitrogen and Carbon atoms and also Carbon and Hydrogen atoms

Nitrogen forms 3 bonds with 3 carbon atoms in N(CH3)3 Lewis structure.

image 116
Step 3:how to draw lewis structure

               

Step 4: Complete octet of central Nitrogen atom

After completing the octet of the central atom, we see that the central nitrogen atom has a lone pair of electrons.

image 122
Lewis Structure of N(CH3)3

                                 

Step 5: Check for the stability of the Lewis structure by finding out the formal charge on atoms in N(CH3)3

Formula for formal charge:

Formal charge = valence electrons – 0.5*bonding electrons – non-bonding electrons

Formal charge on nitrogen:

Formal charge = 5 – 0.5*6 – 2

= 0

The formal charge on nitrogen is 0

Formal charge on carbon atom:

Formal charge = 4 – 0.5*8 – 0

= 0

Formal charge on carbon is 0

Formal charge on hydrogen atom:

Formal charge = 1 – 0.5*2 – 0

= 0

Formal charge on hydrogen is 0

As the formal charge on all the atoms in N(CH3)3 is 0

So, we have got our perfect Lewis structure.

                                      

How many lone pairs are present in the Lewis structure of N(CH3)3?

Formula to find the lone pairs are –

Lone pairs = 0.5*(Valence Electrons of central atom– Number of atoms attached to the central atom)

= 0.5*(5 – 3)

                   = 1

So, the number of lone pair present on the central Nitrogen atom is 1.

 

Does N(CH3)3 follow the octet rule?

N(CH3)3 contains 26 valence electrons. All the atoms in N(CH3)3 have completed their octet as can be seen from the Lewis structure of N(CH3)3. Thus, N(CH3)3 follows the octet rule.

Formal Charge on each atom in the Lewis structure of N(CH3)3

Formula for formal charge:

Formal charge = valence electrons – 0.5*bonding electrons – non-bonding electrons

Formal charge on nitrogen:

Formal charge = 5 – o.5*6 – 2

= 0

The formal charge on nitrogen is 0

Formal charge on carbon atom:

Formal charge = 4 – 0.5*8 – 0

= 0

Formal charge on carbon is 0

Formal charge on hydrogen atom:

Formal charge = 1 – 0.5*2 – 0

= 0

Why is the C-N-C bond angle in N(CH3)3 is 108 degrees?

Due to the repulsion between the lone pair present on the central nitrogen atom and bonded pairs the tetrahedral angle decreases in trimethylamine from 109.5 degrees to 108 degrees.

image 119
Bond Angle in N(CH3)3

                                          

What is the hybridization of Nitrogen in N(CH3)3?

Hybridization of central atom can be found out by using the formula –

Hybridization number = number of atoms attached to the central atom + number of lone pairs present on the central atom

Hybridization Number for Nitrogen in N(CH3)3 = 3 + 1 = 4

so hybridization of central atom nitrogen in N(CH3)3 is sp3.

What is molecular and electron geometry of N(CH3)3 compound?

We know that hybridization of the central atom in N(CH3)3 is sp3 and 1 lone pair is present on the central atom Nitrogen

So according to AXnEx notation of VSEPR theory,

Where –

A is for the central atom

X is for the surrounding atoms, n is number of surrounding atoms

E is for the lone pairs on the central atom, x is for the number of lone pairs.

AXnEx notation for N(CH3)3 is AX3E1 as nitrogen is bonded to three methyl groups and it has a lone pair on it.

Now, AX3E1 notation corresponds to Molecular geometry as Trigonal Pyramidal and Electron Geometry as Tetrahedral in accordance with the VSEPR Chart.

Total Domains General Formula Bonded atoms Lone Pairs Molecular Shape Electron Geometry
1 AX 1 0 Linear Linear
2 AX2 2 0 Linear Linear
AXE 1 1 Linear Linear
3 AX3 3 0 Trigonal Planar Trigonal Planar
AX2E 2 1 Bent Trigonal Planar
AXE2 1 2 Linear Trigonal Planar
4 AX4 4 0 Tetrahedral Tetrahedral
AX3E 3 1 Trigonal Pyramid Tetrahedral
AX2E2 2 2 Bent Tetrahedral
AXE3 1 3 Linear Tetrahedral
VSEPR chart

so the molecular geometry of N(CH3)3 is Trigonal Pyramidal and the Electron geometry is Tetrahedral.

image 120
Geometry of N(CH3)3

                                                

Why is N(CH3)3 a weak base?

N(CH3)3 is a weak base because of presence of bulky methyl groups around the central nitrogen atoms which makes it difficult for the proton to approach for bonding.  

Why is Trimethylamine a polar compound?

Electronegativity of Nitrogen is 3.0 and carbon is 2.5

A molecule is said to be polar when the difference in the electronegativity of its atoms is greater than 0.4

The difference in electronegativity of Nitrogen and Carbon is 0.5

This means that N(CH3)3 has positive and negative ends. This makes N(CH3)3 molecule polar in nature.

Is N(CH3)3 symmetrical or asymmetrical?

N(CH3)3 (Trimethylamine) is asymmetrical molecule as it is a polar molecule and contains positive and negative ends.

Is N(CH3)3 linear?

No, N(CH3)3 is trigonal pyramidal in shape.

Why does N(CH3)3 compound not show resonance?

  • Resonance is shown by such compounds in which there is a possibility for the delocalization of electrons.

In N(CH3)3, the lone pair is localized on the central atom Nitrogen.

  • For showing resonance, all atoms should lie in one plane. In N(CH3)3, the nitrogen is sp3 hybridized so all atoms do not lie in one plane.

That’s why N(CH3)3 compound does not show resonance.

Is N(CH3)3 tetrahedral?

Yes, the electron geometry of N(CH3)3 is tetrahedral as for electron geometry we consider both the bonded atoms as well as the lone pairs

Conclusion:

In a nutshell, N(CH3)3 is a polar compound. The molecular geometry of N(CH3)3 is Trigonal Pyramidal while the Electron Geometry is Tetrahedral. N(CH3)3 is basic in nature.

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