How to draw CH3F Lewis Structure? - Science Education and Tutorials

The fluoromethane chemical formula is CH3F. Drawing CH3F Lewis Structure is very easy to by using the following method. Here in this post, we described step by step method to construct CH3F Lewis Structure. The carbon, fluorine, and hydrogen elements come as the member of the carbon, halogen, and hydrogen family groups from the periodic table respectively. The valence electrons in carbon, fluorine, and hydrogen are four, seven, and one respectively. Fluoromethane is used as an organic volatile solvent in organic fluorinating reactions.

Table of Contents

Key Points To Consider When Drawing The CH3F Structure

A three-step approach for drawing the CH3F Lewis structure can be used. The first step is to sketch the Lewis structure of the CH3F molecule, to add valence electron around the carbon atom; the second step is to add valence electrons to the one fluorine and three hydrogen atoms, and the final step is to combine the step1 and step2 to get the CH3F Lewis Structure.

The CH3F Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the CH3F molecule. The geometry of the CH3F molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose the CH3F geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the C-F bond (dipole moment properties of the CH3F molecule). The carbon-fluorine bonds in fluoromethane(CH3F), for example, are polarised toward the more electronegative fluorine and because both bonds have the same size and are located around four terminals with one fluorine and three hydrogen atoms, their sum is non zero due to the CH3F molecule’s bond dipole moment and the lone pairs of electron on one fluorine atoms. The CH3F molecule is classified as a polar molecule.

The molecule of fluoromethane (with tetrahedral molecular geometry) is tilted, the bond angles between fluorine, carbon, and hydrogen are 109.5 degrees. It has a difference in electronegativity values between carbon and fluorine atoms, with carbon’s pull being less than fluorine’s terminal in the CH3F molecule. As a result, it has the permanent dipole moment. The CH3F molecule has a permanent dipole moment due to an unequal charge distribution of negative and positive charges. The net dipole moment of the CH3F molecule is 1.81 D.

CH3F Lewis Structure:

The central atom is carbon, which is bordered on four terminals with one fluorine atom, three hydrogen atoms, and no lone pair on the carbon in the tetrahedral geometry. Carbon has four outermost valence electrons, indicating that it possesses four electrons in its outermost shell, whereas fluorine only has seven valence electrons in its outermost shell. To complete the octet of the fluorine atom, a fluorine terminal atom requires one electron. If you’re interested in learning more about the fluorine octet rule, please see in our previous post.

One fluorine and three hydrogen atoms establish covalent connections with the central carbon atom as a result, leaving the carbon atom with no lone pair. There is no lone pair on the carbon central atom that resist the bond pairs of the one C-F and three C-H. According to VSEPR theory, no electronic repulsion of the lone pair and bond pair leads the CH3F molecule to take on a tetrahedral molecular geometry shape.

The CH3F molecule’s C-F bonds are arranged in asymmetrical order around the tetrahedral molecular geometry, giving rise to the CH3F molecular shape. The CH3F molecule has a tetrahedral molecular geometry because there is no electrical repulsion between lone pair and bond pairs of CH3F molecule.

Electronegative Difference Calculation of CH3F Molecule:

Calculating the electronegative difference in carbon and fluorine in CH3F

The carbon atom has an electronegativity of 2.55, while fluorine has an electronegativity of 3.98 in the CH3F molecule. The difference in electronegativity can be estimated using the method below.

The electronegative value difference between carbon and fluorine in CH3F molecule
Electronegativity value of carbon in CH3F = 2.55
Electronegativity value of fluorine in CH3F= 3.98
Difference of electronegativity value between carbon and fluorine in CH3F molecule= 3.98 – 2.55 =1.43
Electronegativity difference between C-F bond calculation of CH3F molecule

The electronegative value difference between carbon and hydrogen in CH3F molecule
Electronegativity value of carbon in CH3F = 2.55
Electronegativity value of hydrogen in CH3F= 2.20
Difference of electronegativity value between carbon and hydrogen in CH3F= 2.55 – 2.20 =0.35
Electronegativity difference between C-H bond calculation of CH3F molecule

Due to the difference in electronegativity value of greater than 0.5, the C-F bond of the CH3F molecule becomes polar. Because of this difference in electronegativity, the CH3F molecule’s C-F bond becomes polar. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of CH3F is discussed in our previous post.

As a result, the C-F bond’s dipole moment is high due to the polarization of the bonds, and C-F bonds’ dipoles are arranged at the top of the tetrahedral molecular geometry. The CH3F molecule’s total dipole moment is predicted to be 1.81 D. It has a partial negative charge for fluorine atoms and a partial positive charge for the central carbon atom.

The electron dot structure of the CH3F molecule is also known as the CH3F Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the CH3F molecule’s bond formation. The outermost valence electrons of the CH3F molecule must be understood while considering the Lewis structure of the molecule.

The carbon atom is the middle element in CH3F molecular geometry, with four electrons in its outermost valence electron shell, whereas the fluorine atom has seven electrons in its outermost valence electron shell.

The CH3F molecule has a total of 14 valence electrons as a result of the foregoing above said reasoning. With the core central carbon atom, the four terminal with one fluorine and three hydrogen atoms form covalent bonds, leaving the carbon atom with no lone pairs on it.

The tetrahedral molecular geometry and structure of the CH3F molecules are similar to that of the methane (CH4) molecule. Because no lone pair of a central carbon atom create interaction with C-F bond pairs. The bond angle of the F-C-H bond in the tetrahedral molecular geometry is approximately 109.5 degrees. The C-F and C-H bond lengths are 134 and 107 pm(picometer) respectively.

To sketch the Lewis structure of CH3F by following these instructions:

Step-1: CH3F Lewis dot Structure by counting valence electrons on carbon atom

To calculate the valence electron of each atom in CH3F, look for its periodic group from the periodic table. The carbon and halogen families, which are the 14th and 17th groups in the periodic table, are both made up of carbon and fluorine atoms. In their outermost shells, carbon and fluorine have four and seven valence electrons, respectively.

Because carbon and fluorine are members of the periodic table’s carbon and halogen family groups, their valence electrons are four and seven, respectively.

Calculate the total number of valence electrons in the CH3F molecule’s outermost valence shell. The first step is to determine how many electrons are in the CH3F Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the CH3F Lewis diagram. The CH3Fmolecule’s core carbon atom can be represented as follows:

Total outermost valence shell electron of carbon atom in CH3F= 4
Total outermost valence shell electron of the fluorine atom in CH3F= 7
The CH3F molecule has one central carbon, three hydrogen, and one fluorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for CH3F Lewis structure( dot structure) = 4 +1*7+ 3*1= 14 valence electrons in CH3F
calculation of total valence electron of CH3F molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of CH3F. We’ll choose the least electronegative value atom in the CH3F molecule to place in the center of the CH3F Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

Step-2: Lewis Structure of CH3F for constructing around the terminal hydrogen and fluorine atoms

As a result, carbon is the first atom in the periodic table’s carbon family group. Fluorine is the first member of the halogen family. The electronegative value of the carbon atom is lower than that of the fluorine atom in the CH3F molecule. Furthermore, carbon has a four electrons limit since fluorine is the most electronegative element in the CH3F molecule.

In the CH3F Lewis structure diagram, the carbon atom can be the center atom of the molecule. As a result, central carbon in the CH3F Lewis structure, with all one fluorine and three hydrogens arranged in the tetrahedral geometry.

Add valence electrons around the fluorine atom and add valence hydrogen atom, as given in the figure.

Step-3: Lewis dot Structure for CH3F generated from step-1 and step-2

Connect the exterior and core central atom of the CH3F molecule with four single bonds (one C-F and three C-H). In this stage, use four single bonds to connect all one fluorine and three hydrogen atoms on the outside of the CH3F molecule to the central carbon atom in the middle.

Count how many electrons from the outermost valence shell have been used in the CH3F structure so far. Each C-F bond carries two electrons because each carbon atom is connected to one fluorine and three hydrogen atoms by one C-F and three C-H bonds. Bond pairings of C-F and C-H are what they’re called.

So, out of the total of 14 valence electrons available for the CH3F Lewis structure, we used 8 for the CH3F molecule’s one C-F and three C-H bonds. The CH3F molecule has no lone pair electron in the center of carbon. We need to put no extra electrons in the molecular geometry of CH3F.

Place the valence electrons in the C-H and C-F bond pairs starting with the core carbon, three hydrogen, and one fluorine atoms in the CH3F molecule. In the CH3F Lewis structure diagram, we always begin by introducing valence electrons from the central carbon atom(in step1). As a result, wrap around the central carbon atom’s bond pair valence electrons first (see figure for step1).

Carbon requires 8 electrons in its outermost valence shell to complete the molecular stability, 8 electrons bond pairs in C-H and C-F bonds. Then place no electrons as a lone pair of electrons on the carbon atom of the CH3F molecule. Carbon already shares 8 electrons to the four single C-F and C-H bonds. Then place the valence electron in the fluorine atom, it placed around seven electrons(step-2). Totally, 6 valence electrons were placed on one fluorine atom of the CH3F molecule.

We’ve positioned 8 electrons around the central carbon atom(step-3), which is represented by a dot, in the CH3F molecular structure above. The carbon atom completes its molecular stability in the CH3F molecule because it possesses 8 electrons in its bond pairs with one fluorine and three hydrogens in the outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the CH3F Lewis structure. Four electron bond pairs are shown as dots in the CH3F chemical structure, whereas four single bonds each contain two electrons. The outermost valence shell electrons of the CH3F molecule are 8 +6 = 14 as a result of the calculation.

So far, we’ve used 14 of the CH3F Lewis structure’s total 14 outermost valence shell electrons. No lone pair of electrons on the carbon atom in the tetrahedral geometry of the CH3F molecule.

Complete the middle carbon atom stability and, if necessary, apply a covalent bond. The central carbon atom undergoes octet stability. Because it has a total of eight electrons in the outermost valence shell.

The core atom in the CH3F Lewis structure is carbon, which is bonded to one fluorine and three hydrogen atoms by four single bonds (C-F and C-H). With the help of four single bonds, it already shares eight electrons. As a result, fluorine follows the octet rule and has eight electrons surrounding it on the one terminal of the CH3F molecule’s tetrahedral geometry.

How to calculate the formal charge on a carbon, hydrogen, and fluorine atoms in CH3F molecule?

Calculating formal charge on carbon in CH3F:

The formal charge on the CH3F molecule’s carbon central atom often corresponds to the actual charge on that carbon central atom. In the following computation, the formal charge will be calculated on the central carbon atom of the CH3F Lewis dot structure.

To calculate the formal charge on the central carbon atom of the CH3F molecule by using the following formula:
The formal charge on the carbon atom of CH3F molecule= (V. E(C)– L.E(C) – 1/2(B.E))
V.E (C) = Valence electron in a carbon atom of CH3F molecule
L.E(C) = Lone pairs of an electron in the carbon atom of the CH3F molecule.
B.E = Bond pair electron in C atom of CH3F molecule
calculation of formal charge on carbon atom in CH3F molecule

The carbon core atom (four single bonds connected to one fluorine and three hydrogen atoms ) of the CH3F molecule has four valence electrons, no lone pair of electrons, and eight bonding electrons. Put these values for the carbon atom in the formula above.

Formal charge on carbon atom of CH3F molecule = (4- 0-(8/2)) =0

In the Lewis structure of CH3F, the formal charge on the central carbon atom is zero.

Calculating formal charge on fluorine in CH3F:

The formal charge on the CH3F molecule’s fluorine terminal atom often corresponds to the actual charge on that fluorine terminal atom. In the following computation, the formal charge will be calculated on the terminal fluorine atom of the CH3F Lewis dot structure.

To calculate the formal charge on the terminal fluorine atom of the CH3F molecule by using the following formula:
The formal charge on the fluorine atom of CH3F molecule= (V. E(F)– L.E(F) – 1/2(B.E))
V.E (F) = Valence electron in a fluorine atom of CH3F molecule
L.E(F) = Lone pairs of an electron in the fluorine atom of the CH3F molecule.
B.E = Bond pair electron F atom of CH3F molecule
calculation of formal charge on fluorine atom in CH3F molecule

The fluorine core terminal (one single bond connected with the central carbon atom) of the CH3F molecule has seven valence electrons, six lone pairs of electrons, and two bonding electrons. Put these values for the carbon atom in the formula above.

Formal charge on fluorine atom of CH3F molecule = (7- 6-(2/2)) =0

In the Lewis structure of CH3F, the formal charge on the terminal fluorine atom is zero.

Calculating formal charge on hydrogen in CH3F:

The formal charge on the CH3F molecule’s hydrogen terminal atom often corresponds to the actual charge on that hydrogen terminal atom. In the following computation, the formal charge will be calculated on the terminal hydrogen atom of the CH3F Lewis dot structure.

To calculate the formal charge on the terminal hydrogen atom of the CH3F molecule by using the following formula:
The formal charge on the terminal hydrogen atom of CH3F molecule= (V. E(H)– L.E(H) – 1/2(B.E))
V.E (H) = Valence electron in the hydrogen atom of CH3F molecule
L.E(H) = Lone pairs of an electron in the hydrogen atom of the CH3F molecule.
B.E = Bond pair electron in H atom of CH3F molecule
calculation of formal charge on hydrogen atom in CH3F molecule

The hydrogen terminal atom ( three hydrogen atoms ) of the CH3F molecule has one valence electron, no lone pair of electrons, and two bonding electrons. Put these values for the carbon atom in the formula above.

Formal charge on hydrogen atom of CH3F molecule = (1- 0-(2/2)) =0

In the Lewis structure of CH3F, the formal charge on the terminal hydrogen atom is zero.

Summary:

In this post, we discussed the method to construct the CH3F Lewis structure. First, the valence electrons are placed around the carbon atom. Second, place the valence electron on the fluorine and hydrogen atoms. Finally, when we combined the first and second steps. It gives CH3F Lewis structure. Need to remember that, if you follow the above-said method, you can construct molecular dot structure very easily.