CH3NH2 lewis structure, Characteristics: 13 must to Know Facts


CH3NH2 is the chemical formula for methylamines. CH3NH2 can also be written as CH5N.

Methyl amine (CH3NH2) is an anhydrous liquid or gas with no colour. The odour of methyl amine resembles to the odour of ammonia i.e. fishy pungent odour. Methyl amine has a lowest or simplest alkyl group (methyl group) CH3 and ammonia molecule attached to it. It is an aliphatic primary amine and molecular weight of CH3NH2 is 31.057. At this editorial we are studying about CH3NH2 lewis structure and characteristics.

How to draw CH3NH2 lewis structure?

There are some steps to draw lewis structure of any molecule or chemical compounds. First of all count valence electrons of the atoms and total valence electrons of molecule. Then select the central atom which is least electronegative and make bonding with outer atoms. After bonding the remaining valence electrons get distributed on outer atoms to complete their octets and finally count the formal charge present on central atom and outer atoms.

In CH3NH2 lewis structure, there are total three elements are present one carbon, one nitrogen and five hydrogen atoms. There is one methyl (CH3) group and one amine (NH2) group is present in CH3NH2 molecule. The synonyms for methyl amines are methanamine, aminomethane and monomethyamine.

The C atom, nitrogen atom and hydrogen atom comes under 4th, 15th and 1st group of periodic table.Thus they have 4, 5 and 1 valence electron in their outer valence shell respectively. In CH3NH2 lewis structure, the C and N atom are at central position of CH3NH2 molecule. Carbon atom get surrounded by three hydrogen atoms and N atom surrounded by one carbon, two hydrogen atoms and one lone electron pair.

CH3NH2 valence electrons

The C atom comes under 4th periodic table group, nitrogen atom comes under 5th periodic table group and hydrogen atom comes under 1st group of periodic table. Hence having 4, 5 and 1 valence electrons present in their valence shell outer orbital. Let us count the valence electrons present on CH3NH2 lewis structure.

Carbon atom Valence electrons = 04

Nitrogen atom valence electrons = 05

Hydrogen atoms valence electrons = 1 x 5 = 5

Valence electrons present on CH3NH2 lewis structure = 04 + 05 + 05 = 14

Hence, methy amine CH3NH2 lewis structure has fourteen valence electrons present on it.

If we calculate the total electron pairs present on CH3NH2 molecule divide valence electrons by two.

Total electron pairs on CH3NH2 molecule is = 14 / 2 = 7

Hence, CH3NH2 lewis structure has total seven electron pairs present on it.

Valence electrons On CH3NH2 lewis structures

CH3NH2 lewis structure octet rule

The presence of eight electrons in the outer valence shell of any atom is the octet rule, which tells the presence of eight electrons means the atom has complete octet. In CH3NH2 lewis structure, there are total fourteen valence electrons are present. Out of which twelve electrons are engaged in bonding and being bond pairs.

Therefore, C atom is surrounded with three H atoms and one N atom and forms single covalent bonds with them. Similarly N atom is surrounded by two H atom and one C atom and form single covalent bond between them with extra lone pair remain on it. Thus, the central C and N atoms are having four and three covalent bonds with one lone pair.

 Means C and N atom is surrounded with eight – eight electrons pairs i.e. four – four electron bond pairs. As the carbon atom has eight electrons and nitrogen atom also has eight electrons, so the carbon and nitrogen atoms has complete octet. Octet rule does not apply on H atoms as they can only possess maximum two electrons in their outer valence shell orbitals.

CH3NH2 lewis structure showing complete octet of C and N atoms

CH3NH2 lewis structure formal charge

Formal charge counting or calculation is done by using a given formula as follows:

Formal charge = (valence electrons – non-bonding electrons – ½ bonding electrons)

Formal charge calculation of CH3NH2 lewis structure can be done through the counting of formal charge of each atom present on CH3NH2 i.e. carbon, nitrogen and hydrogen atoms as shown as follows:

Carbon atom: Carbon atom have Valence electrons = 04

                       Carbon atom have Non- bonding electrons = 00

                       Carbon atom have Bonding electrons = 08 (2 electrons in single bond)

Formal charge on carbon atom is = (04 – 00 – 08/2) = 0

So, the carbon atom of CH3NH2 lewis structure has zero formal charge.

Nitrogen atom: Nitrogen atom have Valence electrons = 05

                          Nitrogen atom have non- bonding electrons = 02

                            Nitrogen atom have Bonding electrons = 06 (2 electrons in single bond)

Formal charge on nitrogen atom is = (5 – 2 – 6/2) = 0

So, the nitrogen atom of CH3NH2 lewis structure has zero formal charge.

Hydrogen atom: Hydrogen atom have Valence electrons = 01

                           Hydrogen atom have Non- bonding electrons = 00

                             Hydrogen atom have Bonding electrons = 2 (2 electrons in single bond)

Formal charge on hydrogen atom is = (01 – 00 – 2/2) = 0

So, the hydrogen atom of CH3NH2 lewis structure has zero formal charge.

Hence, the entire C, N and H atoms of CH3NH2 lewis structure has zero formal charge.

Formal charge on CH3NH2 lewis structure

CH3NH2 lewis structure lone pairs

The CH3NH2 lewis structure has total three elements C, N and H. It has two central atoms i.e. C and N atoms. Carbon atom is enclosed with the hydrogen atoms and one amine (NH2) molecule. Nitrogen atom is enclosed with two hydrogen atoms and one methyl (CH3) group. Carbon atom is bounded with four molecules having four bonding electron density i.e. four bond electron pairs as there is three C-H single covalent bonds and one N-H single covalent bond.

Likewise nitrogen atom is bounded with three molecules having three bonding electron density i.e. three bond electron pairs as there is two N-H single covalent bonds and one C-N single covalent bond. Also there is one lone electron pair is present on nitrogen atom. So, the octets of both C and N atoms get completed. Thus, CH3NH2 lewis structure has only one lone electron pair which is present on nitrogen atom.

CH3NH2 lewis structure resonance

Any molecule can show resonance structure only if there are multiple bonds i.e. triple bond or double bonds are present in its structure. Also there should be at least one lone electron pair is present and also have some formal charge present on it. Then only the resonance structure of any molecule can possible.

In case of CH3NH2 lewis structure, there is no multiple bonds are present. All the bonds within carbon – nitrogen, nitrogen – hydrogen and carbon – hydrogen bonds are single covalent bonds which are strong bond and cannot easily breaks. Also there is a single lone electron pair is present on nitrogen atom. But all the atoms C, N and H atoms of CH3NH2 lewis structure has zero formal charge present on it.

Thus, CH3NH2 lewis structure does not obey all the conditions applied to draw the resonance structure. As, there is no multiple bon and formal charge is present on CH3NH2 lewis structure. Hence, the resonance structure of CH3NH2 molecule or lewis structure is not possible.

CH3NH2 lewis structure shape

In CH3NH2 lewis structure, there are two groups are present i.e. methy group (CH3) and amine group (NH2). So, there are two central metal atoms i.e. carbon atom and nitrogen atom in CH3NH2 lewis structure. If we see the first group i.e. CH3 methyl group, the central carbon atom is surrounded with four more moieties i.e. three hydrogen atoms and one NH2 amine group is surrounded to central carbon atom.

Similarly, the nitrogen atom is surrounded by three groups and one lone pair electron i.e. two hydrogen atom and one CH3 methyl group is surrounded to central nitrogen atom. Thus C atom surrounded by four moieties and N atom surrounded by three moieties, Then according to VSEPR theory, carbon atom follows AX4 generic formula and nitrogen atom follows AX3E1 generic formula. A= central atom, X = bonded atoms and E = lone pair electron.

So, the central carbon atom has tetrahedral molecular geometry and tetrahedral shape as it follows AX4 generic formula as it is attached to four bonded groups. Likewise central nitrogen atom has molecular geometry trigonal pyramidal and tetrahedral shape as it follows AX3E generic formula as it is attached to three bonded groups and has one lone electron pair.

ch3nh2 lewis structure
Shapes of CH3NH2 lewis structure

CH3NH2 hybridization

CH3NH2 lewis structure has two molecular geometries and two shapes. As per the VSEPR theory, the CH3NH2 molecules carbon atoms follow AX4 generic formula and have tetrahedral molecular geometry and tetrahedral shape too and the nitrogen central atom follow AX3E generic formula and have trigonal pyramidal geometry and tetrahedral shape.

Thus, according to VSEPR theory both the AX4 and AX3E generic formula has sp3 hybridization. Hence, carbon atom of CH3NH2 has tetrahedral geometry as it follows AX4 generic formula so it is has sp3 hybridization. Similarly, nitrogen atom of CH3NH2 has trigonal pyramidal geometry as it follows AX3E generic formula so it has sp3 hybridization. Therefore, CH3NH2 lewis structure has sp3 hybridization.

CH3NH2 lewis structure angle

As both the central atoms of CH3NH2 lewis structure i.e. carbon atom and nitrogen atom has followed VSEPR theory’s AX4 and AX3E generic formula. So, the carbon atom has tetrahedral molecular geometry and tetrahedral shape also it has sp3 hybridization. Thus, central carbon atom has hydrogen carbon hydrogen (H-C-H) and hydrogen carbon nitrogen (H-C-N) bond angle of 109.5 degree.

Likewise, the nitrogen atom has trigonal pyramidal molecular geometry and tetrahedral shape also it has sp3 hybridization. Thus, central nitrogen atom has hydrogen nitrogen hydrogen (H-N-H) and hydrogen nitrogen carbon (H-N-C) bond angle of 109.5 degree. Thus, all the bond angles of CH3NH2 lewis structure is 109.5 degree.

CH3NH2 solubility

Methyl amine (CH3NH2) is soluble in:

  • Water
  • Benzene
  • Acetone
  • Diethyl ether
  • Methanol
  • Ethanol
  • Aniline
  • Isobutanol
  • Quinoline

Is CH3NH2 ionic?

No, CH3NH2 is not ionic rather it is a covalent molecule.

Why CH3NH2 is not ionic?

All the bonds present in CH3NH2 lewis structure is single covalent bonds, as it cannot form ions. Thus CH3NH2 is a covalent molecule.

How CH3NH2 is not ionic?

There is no ionic bond present in CH3NH2 molecule. Only single strong covalent carbon hydrogen (C-H), carbon nitrogen (C-N) and nitrogen hydrogen (N-H) bonds are present. Thus it is not ionic but covalent in nature.

Is CH3NH2 acidic or basic?

Methyl amine (CH3NH2) is basic in nature. It act as weak base also bronstead base and lewis base.

Why CH3NH2 is basic?

When CH3NH2 reacts with water it accepts H+ proton from water molecule and release OH- ions in the solution. In water CH3NH2 works as a strong base as it has pKb value 3.36. It is a vital nucleophile. As there is a lone pair electron is present on nitrogen atom of CH3NH2 molecule, the H+ proton gets added on NH2 molecule and forms a positively charge NH3+ ion with the release of OH- (hydroxyl) ion in the solution.

CH3-NH2 + H2O ⇌ CH3-NH3+ + OH

How CH3NH2 is basic?

CH3NH2 is a weak base as it does not completely dissolve in water. Weak base is the compound that incompletely or partially dissolves in water. Means some of the compound get dissolve in water to produce OH- hydroxyl ion and remaining part is not dissolved. So, CH3NH2 molecule is also not completely dissolved in water and it is a weak base.

Is CH3NH2 polar or nonpolar?

Methyl amine (CH3NH2) is a polar molecule in nature.

Why CH3NH2 is polar?

The electronegativities of C, H and N atoms of CH3NH2 molecule is 2.5, 2.2 and 3.04 respectively. So, there is a quite high electronegativity difference between atoms of CH3NH2 molecule and hence, it is polar in nature.

How CH3NH2 is polar?

In CH3NH2 molecule, dipole moment creates along the N atom of C-N bond. Also dipole moment creates on N-H bond because of lone electron pair present on N atom. Also the H is less electronegative than N thus the dipole moment goes towards the N atom. Hence CH3NH2 molecule is polar in nature.

Is CH3NH2 tetrahedral?

Yes, CH3NH2 molecule has tetrahedral shape.

Why CH3NH2 is tetrahedral?

The molecular geometry and shape of C and N atom of CH#NH2 molecule is tetrahedral. Thus, CH3NH2 has a tetrahedral geometry.

How CH3NH2 is tetrahedral?

The C and N atom of CH3NH2 molecule follows VSEPR generic formula AX4 and AX3E which shows the tetrahedral shape of molecule.

Is CH3NH2 linear?

No, CH3NH2 is not a linear molecule.

Why CH3NH2 is not linear?

Because both the C and N atoms have tetrahedral and trigonal pyramidal geometry thus it is not linear.

How CH3NH2 is not linear?

The bond angles of CH3NH2 molecule is 109.5 degree and the linear molecule has 180 degree bond angle. Hence it is not linear.

Conclusion:

CH3NH2 has 14 valence electrons, one lone pair electron with complete octet of C and N atoms. It has tetrahedral and trigonal pyramid geometry with sp3 hybridization and 109.5 degree bond angle. It is a covalent molecule, basic and polar in nature.

Dr. Shruti Ramteke

Hello everyone I am Dr. Shruti M Ramteke, i did my Ph.D in chemistry. I have five years of teaching experience for 11-12 standard, B,Sc and MSc in chemistry subject. I have published total five research articles during Ph.D on my research work and i have fellowship from UGC for my Ph.D. My Masters with specilization Inorganic chemistry and my graduation with chemistry, zoology and environmental science subjects. thank You

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