CH3NH2 Lewis Structure, Molecular Geometry, Hybridization, Polar or Nonpolar

CH3NH2 Lewis Structure, Molecular Hybridization, Polar or Nonpolar Geometry, Methylamine, often known as CH3NH2, is a colorless gas with a fishy, ammoniacal odor. This gas is an ammonia derivative with one hydrogen atom substituted by a methyl group. It's the most basic primary amine. Methylamine is carried in the anhydrous form in pressurized railcars and tank trailers in the industrial sector. Methylamine is a key component in the production of a wide range of commercially accessible chemicals. The simplest aliphatic amine present in human urine is methylamine. It is hypothesized to play a role in central nervous system problems seen in renal and hepatic disease, as well as in general toxicity induced by oxidative stress in the body. Production of Methylamine Methylamine can be produced through the industrial process and also in laboratory for research purposes. 1) By industrial method Commercially, methylamine is made by reacting ammonia with methanol in the presence of an aluminosilicate catalyst. Dimethylamine and trimethylamine are created in tandem; the ratio of the three products is determined by reaction kinetics and reactant ratios. Trimethylamine is the product that the reaction kinetics favor the greatest. CH3OH + NH3 → CH3NH2 + H2O 2) By laboratory method Methylamine hydrochloride can be easily made in the lab using a variety of ways. The use of ammonium chloride to treat formaldehyde is one way. NH4Cl + H2CO → [CH2=NH2]Cl + H2O [CH2=NH2]Cl + H2CO + H2O → [CH3NH3]Cl + HCO2H Properties of Methylamine: ➔ Methylamine is a colorless gas with a fishy, ammoniacal odor. ➔ It is an ammonia derivative with one hydrogen atom substituted by a methyl group. ➔ The melting point and boiling point of CH3NH2 are -93.10°C and -6.6°C to -6.0°C respectively. ➔ It has a molar mass of 31.058 g/mol and a density of 656.2 g/m3 at 25°C. ➔ It has a vapor pressure of 186.10 kPa at 20°C. Uses of Methylamine: ➔ Pharmaceuticals like ephedrine and theophylline, as well as insecticides like carbofuran, carbaryl, and metham sodium, are all made from methylamine. ➔ Because it is an unrestricted amine, methylamine is a good nucleophile. ➔ It is widely used in organic chemistry. CH3NH2 Lewis structure A Lewis Structure, also known as an Electron Dot Structure, is a simplified representation of a molecule's valence shell electrons. It refers to the arrangement of valence electrons surrounding particular atoms in a molecule. Gilbert N. Lewis introduced the Lewis structure in his 1916 article "The Atom and the Molecule," and it was named after him. Electrons are shown as "dots" surrounding the central metal atom in a Lewis Structure. The center metal is identified by its Periodic Table chemical symbol. A line is used to symbolize the bonding electrons between two combining atoms in Lewis Structures. The number of lone pairs of electrons present surrounding the central atom is also indicated by the Lewis Structure. Lewis Ionic, covalent, and coordination compounds all have structures that can be drawn. However, we can only draw it if we know the compound's molecular formula. The atomic state of elements can also be represented. It is a feature that favors covalent compounds and is used to investigate formal charges on the involved atoms as well as chemical bonding between them. The diagrams are called resonance structures when more than one Lewis diagram can be generated for a molecule. To begin, it's important to know how many valence electrons each participating element has in order to comprehend the Lewis structure of methylamine (CH3NH2). Valence electrons The valence electrons are those on an atom that can be gained or lost in a chemical process. They are found in the outermost shell. The reactivity of an element is determined by its valence electrons. They determine how "willing" the elements are to generate new compounds by determining how "willing" they are to bind with one other. When an element's valence shell is full, as it is in the case of a noble gas, the element does not desire to gain or lose an electron. Octet Rule The octet rule describes atoms' preference for having eight electrons in their valence shell. Atoms with fewer than eight electrons have a higher proclivity for reacting and forming more stable compounds. We don't consider d or f electrons while considering the octet rule. The octet rule only involves the s and p electrons, which makes it useful for main group elements (those not in the transition metal or innertransition metal blocks); an octet in these atoms corresponds to an electron configuration ending in s2p6. Formal charge A formal charge (FC) is a charge assigned to an atom in a molecule based on the assumption that electrons in all chemical bonds are shared equally among atoms, regardless of relative electronegativity. When choosing the optimum Lewis structure (or predominant resonance structure) for a molecule, it is important to keep the formal charge on each of the atoms as low as feasible. The following equation can be used to compute the formal charge of any atom in a molecule: Formal Charge (FC) = V- N – B/2 where V denotes the number of valence electrons on the neutral atom in its ground state; N denotes the number of non-bonding valence electrons on this atom in the molecule, and B is the total number of electrons shared in bonds with other atoms. Steps for drawing Lewis dot structure of CH3NH2 Step 1. Count the total number of valence electrons present on each atom of the CH3NH2 molecule In modern periodic table, Carbon's electrical configuration is 1s2 2s2 2p2 due to its atomic number of 6. Because the p shell can only hold a maximum of 6 electrons, there is a vacancy of 4 electrons, giving carbon 4 valence electrons. Furthermore, because their atomic numbers are 1 and 7, hydrogen and nitrogen have electronic configurations of 1s1 and 1s2 2s2 2p1. To sustain their octet, the s shell can accommodate 2 valence electrons and the p shell can accommodate 6, hence the valence electron for hydrogen is 1 and the valence electron for nitrogen is 5. Mathematically, Valance electrons of CH3NH2 = valance electrons of (1 carbon+ 5 Hydrogen + 1 Nitrogen) Therefore, valance electrons of CH3NH2= 4+ 1*5 + 5 =14 valance electrons. Hence, the valence electrons of CH3NH2 are 14 valance electrons. Step 2. Determine the total number of valence electrons pairs for CH3NH2 molecules By summing the bonds and lone pairs of electrons in the molecule, the valence electron pair of the molecule can be computed. The two types of bonding are sigma and pi. Summing sigma bonds, pi bonds, and the lone pair of electrons in a molecule yield the valence electron pair of the molecule. Total valence electrons= sigma bonds+pi bonds+lone pairs at valence shell (mathematically). The total number of valence electron pairs in the molecule can be estimated by dividing the total number of valence electrons in the molecule by two. In the case of the CH3NH2 compound, the total number of valance electrons pairs is 14/2 i.e7. Step 3. Identify the Central atom and draw a simple skeleton diagram. All other atoms are held together by the center atom. The identification of a central atom is crucial for drawing the Lewis structure of a molecule. There are numerous methods for determining a molecule's core atom. Calculating the number of bonds each atom creates in a molecule is the simplest of these procedures. The center atom in a molecule is likely to be the atom that forms the most bonds. In the case of CH3NH2, Three hydrogen atoms are connected to the carbon atom, while two are bonded to the nitrogen atom, as shown by the chemical formula. As a result, CH3 and NH2 are two distinct entities with two central atoms, carbon and nitrogen. Step 4. Put lone pairs of electrons on each atom. In order to complete their octet, all atoms (except H and He, which require two electrons on the outer shell) require eight electrons on the outer (valence) shell. To complete their octet, the atoms form bonds with other atoms in the molecule. It's possible that bonding does not involve all of the electrons in the valence shell. Chemical bonding is not possible with non-bonding or lone pair electrons, but it is possible with bonding or lone pair electrons. Three hydrogen atoms are connected to the carbon atom, while two are bonded to the nitrogen atom, as shown by the chemical formula. Because methylamine (CH3NH2) is an amine, a single bond forms between the involved atoms with a lone pair of electrons on the nitrogen atom. Step 5. Complete the octet of all the atoms and make a covalent bond if necessary. In case of CH3NH2, Carbon's electrical configuration is 1s2 2s2 2p2 due to its atomic number of 6. Because the p shell can only hold a maximum of 6 electrons, there is a vacancy of 4 electrons. So, in order to complete the octet rule, they require 4 valance electron. Furthermore, because their atomic numbers are 1 and 7, hydrogen and nitrogen have electronic configurations of 1s1 and 1s2 2s2 2p1. To sustain their octet, the s shell can accommodate 2 valence electrons and the p shell can accommodate 6. In this way, all atoms of CH3NH2 acquire a stable state and complete the octet rule. Step 6. Calculate the formal charge distribution on all atoms and check the stability. The formal charge of an atom is a quantity that indicates whether the atom is electrostatically balanced or not. It is the difference between the number of valence electrons in the neutral atom and the number of valence electrons around the atom in the molecule. A formula can be used to compute formal charge: Formal charge (FC) = [Valence electrons (V) – Lone pair electrons (L) -Bonded pair electrons (B)/2] In the case of CH3NH2, The formal charge of C = 4-0-8/2 =0 The formal charge of H = 1-0-(½)*2= 0 The formal charge of N= 5-2-6/2 =0 Since, the formal charge of all atoms i.e hydrogen, carbon, and nitrogen are found to be zero. We can conclude that CH3NH2 is electrostatically balanced and form the suitable lewis structure. CH3NH2 Molecular Geometry & Shape The Lewis structure determines the bond length, angles, type, and other geometrical features of a molecule's molecular geometry, which is based on the position of each of the participating atoms. Because Methylamine (CH3NH2) has two central atoms, the molecular geometry of both will be different due to the bond angles. The molecular geometry of carbon primarily targeting -CH3 will be tetrahedral. The molecular geometry of nitrogen targeting the -NH2 end is trigonal pyramidal. According to the Valence Shell Electron Pair Repulsion Theory (VSEPR), "Whenever there is a repulsion between pairs of valence electrons in all atoms, the atoms will arrange themselves in a geometric shape to minimize the electron pair repulsion." The goal is for the molecule to have the least amount of energy and the greatest amount of stability. The molecular geometry of CH3NH2 can also be predicted using AXN notation by VSEPR rule. AXN notation of Nitrogen in CH3NH2: A = A center atom is Nitrogen. X = The number of bonds linked to Nitrogen. 2 Hydrogen atoms and 1 carbon atom is linked to the central atom Nitrogen. N = There is one lone pair on the nitrogen atom. As a result, AX3N1 is the general formula for CH3NH2. The geometry of a molecule is trigonal pyramidal if its central atom has three bonded atoms and one lone pair, according to the VSEPR chart. AXN notation of carbon in CH3NH2: A = A center atom is carbon. X = The number of bonds linked to carbon. 3 hydrogen atoms and 1 nitrogen atom is linked to central atom carbon. N = There are no lone pairs on the carbon atom. As a result, AX4 is the general formula for CH3NH2. The geometry of a molecule is tetrahedral if its central atom has four bonded atoms and no lone pair, according to the VSEPR chart. Bond angle of CH3NH2 The angle produced between two covalent bonds that originate from the same atom is known as the bond angle. Since Methylamine (CH3NH2) has two central atoms. They have a different bond angle. As the forming bond angles are 109.5° because the molecular geometry of carbon primarily targeting -CH3 is tetrahedral. The molecular geometry of nitrogen targeting the -NH2 end is trigonal pyramidal, with a bond angle of roughly 108.9°. CH3NH2 Hybridization When two atomic orbitals of a molecule combine to generate a hybrid orbital, the energy of the orbitals of individual atoms is redistributed to give orbitals of equivalent energy. This is known as hybridization. Hybridization involves the merging of two 's' orbitals or two 'p' orbitals, or the mixing of an's' orbital with a 'p' orbital, as well as an 's' orbital with a 'd' orbital. Hybrid orbitals are the new orbitals created in this way. More importantly, hybrid orbitals can be used to explain atomic bonding and molecular geometry. The hybridization number for CH3NH2 can be calculated using the formula provided: Hybridization number = (number of atoms bonded to carbon + number of lone pairs on carbon) Or simply, we can predict the hybridization of any compound from the given steps. ● If the total number of valence electrons is less or equal to 8, divide it by 2. (V.E. < 8 divided by 2) ● If the total number of valence electrons of a molecule is between 8 to 56, divide it by 8. (8 < V.E < 56 divided by 8) ● Similarly, if the valence electrons of a given molecule are more than 56, divided by 18. (V.E.>56 divided by 18) In the case of CH3NH2, the total valence electrons are 14. So, it is divided by 8. This results in quotient 1 and remainders 6. Since the remainder is non-zero, it is further divided by 2 which results in quotient 3 and remainder 0. Since the total number of orbitals is 4. so, the hybridization of both carbon and nitrogen in CH3NH2 forms sp3 hybridization. IS CH3NH2 POLAR OR NONPOLAR? Polarity is a feature that allows chemical molecules to choose whether or not to attract a surrounding atom. Chemical polarity causes electrical charges to separate, resulting in a net dipole moment on the molecule with one positively charged end and the other negatively charged. Because of the electronegativity disparities among the component atoms, methylamine (CH3NH2) is a polar molecule with a dipole moment on the overall molecule. Carbon, hydrogen, and nitrogen have electronegativity values of 2.55, 2.20, and 3.04, respectively. CH3NH2 polarity is determined by three components: 1. Electronegativity: The number of valence electrons and their distance from the nucleus determine the value of electronegativity. It's important to note that the bigger the number of valence electrons, the greater the ability to attract electrons and hence the higher the electronegativity value. The lesser the tendency to attract the electrons (they will be donated) and the lower the electronegativity value, the fewer the number of valence electrons. Carbon, hydrogen, and nitrogen have electronegativity values of 2.55, 2.20, and 3.04, respectively. Because the nitrogen atom has the largest electronegativity, the dipole moment around it will be the highest, resulting in polarity in the methylamine (CH3NH2) molecule. 2. Dipole moment The dipole moment will flow towards nitrogen in the case of carbon and nitrogen bonding because nitrogen's electronegativity value is larger. Because of the presence of a lone pair on the nitrogen atom, the dipole moment will be added up again in the case of nitrogen and hydrogen bonds, and the dipole moment will shift upward, in the direction of the nitrogen atom. The connection will be nonpolar in nature due to the small difference between the carbon and hydrogen atoms, but its intensity will be far less than the dipole moment around the nitrogen atom. As a result, methylamine (CH3NH2) is a polar molecule. 3. Geometrical or molecular shape The polarity of a molecule can be influenced by the geometry structure because an asymmetrical shape distributes unequal charges in the molecule, making it difficult to cancel out the dipole moment. Because Methylamine (CH3NH2) has two central atoms, the molecular geometry of both will be different due to the bond angles. The molecular geometry of carbon primarily targeting -CH3 will be tetrahedral. The molecular geometry of nitrogen targeting the -NH2 end is trigonal pyramidal. However, a tetrahedral geometry can only be asymmetrical if one or more atoms in the molecule deviate from the others. This causes a dipole moment. As a result, CH3NH2 has an asymmetrical molecular geometry with a tetrahedral form and trigonal pyramidal, which makes it polar in nature. Summary ➔ Methylamine is a colorless gas with a fishy, ammoniacal odor. ➔ It is an ammonia derivative with one hydrogen atom substituted by a methyl group. ➔ Methylamine (CH3NH2) is a nucleophile. ➔ Both the central atoms are sp3 hybridized. ➔ Because of the strong dipole moment on the nitrogen atom and negligible on the carbon-hydrogen bond, the methylamine molecule is polar in nature.