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

The sodium chloride chemical formula is NaCl. Drawing NaCl Lewis Structure is very easy to by using the following method. Here in this post, we described step by step method to construct NaCl Lewis Structure. The chlorine and sodium elements come as members of the halogen and alkaline metal family groups from the periodic table respectively. The valence electrons in chlorine and sodium are seven and one respectively. Sodium chloride is used to make chemical reagents for organic chemical reactions as a brominating agent in organic chemistry.

Table of Contents

Key Points To Consider When Drawing The NaCl Electron Dot Structure

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

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

Finally, you must add their bond polarities to compute the strength of the one Na+—Cl- single bonds (dipole moment properties of the NaCl molecule). The sodium-chlorine ionic bonds in sodium chloride(NaCl), for example, are polarised toward the more electronegative chlorine in NaCl molecule, and because both bonds have the same size and are located around one sodium terminal of the linear structure with three lone pairs (in total eight electrons) on the chlorine atom as chloride ion(Cl-), their sum of dipole moment is nonzero due to the NaCl molecule’s bond dipole moment and less electron polarity to the sodium atoms and become sodium ion. Because Na+—-Cl- bonds polarity is not canceled in the NaCl molecule due to the presence of four lone pairs of electrons in the linear structure. The sodium chloride(NaCl) molecule is classified as a polar ionic molecular crystal.

The molecule of sodium chloride(linear-shaped molecular geometry) is tilted, the bond angles between chlorine (as chloride ion) and sodium (as sodium ion) are 180 degrees. It has a difference in electronegativity values between chlorine and sodium atoms, with central chlorine’s pull being higher than terminal sodium’s in the NaCl ionic molecule. But they do not cancel each other due to the linear structure with four lone pairs in the molecular geometry of the NaCl molecule.

As a result, it has the nonzero dipole moment. The NaCl molecule has a nonzero dipole moment due to an unequal charge distribution of negative and positive charges. But both chlorine and sodium atoms fall on the halogen and alkaline metal family groups in the periodic table respectively. The chlorine atom is a more electronegative value than sodium in the NaCl ionic molecule. The NaCl molecule has the net dipole moment of non-zero value in the ground state energy level.

NaCl molecule has one Na+—–Cl- single bond. Its dipole moment in the ground state is totally different as compared with the excited state. If it absorbs light may be from visible or UV light. It undergoes pi to pi star and n to pi star transition from ground state energy level to excited state energy level. In the excited state energy level, the NaCl ionic molecule shows a definite dipole moment. But it is very dynamic in nature.

Molecules can be classified as polar or nonpolar. The molecule polar behaves in a different manner as compared to nonpolar.

Overview: NaCl Lewis Structure

The central atom is chlorine, which is bordered on two terminals with sodium atoms(linear structural geometry), and four lone pairs on the central chlorine atom in the linear molecular geometry. Chlorine has seven outermost valence electrons, indicating that it possesses seven electrons in its outermost shell, whereas sodium also has one valence electron in its outermost shell. To complete the octet of the chlorine atom requires one valence electron on each of their outermost shell.

One sodium atom establishes covalent connections with the central chlorine atom as a result, leaving the chlorine atom with three lone pairs. There are three lone pairs of electrons on the chlorine central atom that resists the bond pairs of the Na+—-Cl- bond. According to VSEPR theory, the Na+—-Cl- ionic bond pairs polarity lead the NaCl molecule to take on the linear geometry structure.

The NaCl molecule’s one Na+—-Cl- bonds are arranged in asymmetrical polarity order around the linear molecular geometry, giving rise to the NaCl molecular shape. The NaCl molecule has a linear molecular geometry because there is an electrical repulsion between the lone pairs of electrons in chlorine and one single ionic bond pair(Na-Cl) of the NaCl molecule.

Lewis structure of NaCl has dot electron representative structure. Valence electrons of atoms undergo orbitals mixing in the chemical reactions, giving new types of molecular species of NaCl. The molecule is nothing but a bundle of valence electrons from the atoms. But it is converted to ionic bond pairs and lone pairs in the molecular structure.

Electronegative value Difference Calculation of NaCl Molecule:

Chlorine and sodium Electronegative difference in NaCl:

The chlorine atom has an electronegativity of 3.16, while sodium has an electronegativity of 0.93 in the NaCl ionic molecule. The difference in electronegativity of chlorine and sodium can be estimated using the method below.

The electronegative value difference between chlorine and sodium in NaCl molecule
Electronegativity value of chlorine= 3.16
Electronegativity value of sodium= 0.93
Difference of electronegativity value between chlorine and sodium in NaCl molecule = 3.16 – 0.93 = 2.23
Electronegativity difference between Na-Cl ionic bond calculation of NaCl molecule

The electronegative difference between chlorine and sodium is greater than 0.5. This indicated the bond polarity moves near to polar nature. Na-Cl ionic bond polarity in the NaCl molecule is polar.

Because of this difference in electronegativity of chlorine and sodium atoms, the NaCl molecule’s Na+—Cl- bond becomes nonpolar. The total net dipole moment of the NaCl molecule is nonzero due to the cancellation of the bond dipole moment in the linear geometry due to the presence of three lone pairs of electrons. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side.

As a result, the Na-Cl bond’s dipole moment is higher due to the polarization of the bonds and four lone pairs of electrons on chlorine, and all Na-Cl bonds’ dipoles are arranged in the asymmetrical NaCl molecular geometry. The NaCl molecule has a nonzero net dipole moment.

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

The chlorine atom is the middle element in NaCl molecular geometry, with seven electrons in its outermost valence electron shell, whereas the sodium atom has one electron in its outermost valence electron shell. The sodium atom has one valence electron.

The NaCl has a total of 8 valence electrons as a result of the foregoing above-said reasoning. With the core central chlorine atom, the one terminals with one sodium atom form ionic bonds, leaving the chlorine atom with four lone pairs in the middle of linear geometry.

Because three lone pairs on the terminal chlorine atoms create interaction with Na-Cl bond pairs(but it is negligible in the ground state of the NaCl molecule). The bond angle of the Na-Cl bond in the linear molecular geometry is approximately 180 degrees. This angle is greater than the CH4 molecule bond angle. The Na-Cl bond length is 250 pm(picometer).

To sketch the NaCl Lewis structure by following these instructions:

Step-1: NaCl Lewis dot Structure by counting valence electrons on the chlorine atom

To calculate the valence electron of each atom in NaCl, look for its periodic group from the periodic table. The halogen and alkaline metal group families, which are the 17th and 1st groups in the periodic table, are both made up of chlorine and sodium atoms respectively. In their outermost shells, sodium and chlorine have one and seven valence electrons respectively.

Calculate the total number of valence electrons in the NaCl molecule’s outermost valence shell. The first step is to determine how many electrons are in the NaCl 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 NaCl Lewis diagram. The NaCl molecule’s core chlorine atom can be represented as follows:

Total outermost valence shell electron of chlorine atom in NaCl= 7
Total outermost valence shell electron of sodium atom in NaCl= 1
The NaCl molecule has one central chlorine and one sodium atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for NaCl Lewis structure( dot structure) = 7+1*1= 8 valence electrons in NaCl.
calculation of total valence electron of NaCl molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of NaCl. We’ll choose the least electronegative value atom in the NaCl molecule to place in the center of the NaCl Lewis structure diagram in this phase.

But in this case, sodium is the least electronegative than chlorine. Sodium loses one electron and forms sodium positive ions(Na+). So that chlorine stays in the central molecular structure. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

The first step is to put seven valence electrons around the sodium atom as given in the figure.

Step-2: Lewis Structure of NaCl for counting valence electrons around the terminal sodium atoms

As a result, chlorine is the second atom in the periodic table’s halogen family group. Sodium is the third member of the alkaline metal family. It is the third element in the periodic table. The electronegative value of the chlorine atom is higher than that of the sodium atom in the NaCl molecule. Furthermore, sodium has a one-electron limit since it is the less electronegative element in the NaCl molecule.

In the NaCl Lewis structure diagram, the chlorine atom can be the center atom of the molecule. As a result, central chlorine in the NaCl Lewis structure, with one sodium atom arranged in a linear geometry.

Chlorine accepts one electron and forms a chloride ion(Cl-). The total lone pair of electrons in the chloride ion is eight. They are negatively charged.

Add valence electron around the chlorine atom, as given in the figure.

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

Connect the exterior and core central atom of the NaCl molecule with one single Na-Cl bond. In this stage, use one sodium atom on the outside of the NaCl molecule to the central chlorine atom in the middle.

Count how many electrons from the outermost valence shell have been used in the NaCl structure so far. Na-Cl single bond carries two electrons because the chlorine atom is connected to one sodium atom by Na-Cl single bonds. Bond pairings of Na-Cl are what they’re called.

So, out of the total of 8 valence electrons available for the NaCl Lewis structure, we used four electrons for the NaCl molecule’s one Na-Cl single bond. The NaCl molecule has three lone pairs of electrons in the central chlorine atom.

Place the valence electrons in the Na-Cl bond pair starting with the core chlorine, one sodium atom in the NaCl molecule. In the NaCl Lewis structure diagram, we always begin by introducing valence electrons from the central chlorine atom(in step 2). As a result, wrap around the central chlorine atom’s bond pair valence electrons first (see figure for step2).

The chlorine atom in the molecule gets only 8 electrons around its molecular structure. This central chlorine atom is octet stable. But it has three lone pairs. Chlorine gas(Br2) is a brownish liquid gas. chlorinehlorine is very corrosive in nature. It is one of the very reactive chemical reagents.

Sodium metal is in a soft solid state at normal temperature and pressure. It is used as a reducing agent in the field of organic chemistry. It is highly flammable in nature. It is very reactive in water and alcohol. Water reacts with sodium metal and forms sodium hydroxide. Similarly, alcohol(such as methanol) reacted with sodium and forms sodium methoxide.

Chlorine requires 8 electrons in its outermost valence shell to complete the molecular octet stability, two electrons bond pairs in one Na-Cl single bond, and three lone pairs in the central chlorine atom. No lone pairs of electrons on the sodium atoms of the NaCl molecule are placed in a linear geometry. Chlorine already shares 8 electrons to the one Na-Cl single bonds. Then place the valence electron in the sodium atoms, it placed around one electron on each atom(step-1). There are no valence electrons placed around one sodium atom as lone pair of electrons.

We’ve positioned 8 electrons around the one-terminal sodium atoms(step-3), which is represented by a dot, in the NaCl molecular structure above. The chlorine atom completes its molecular octet stability in the NaCl molecule because it possesses 2 electrons in its (one Na-Cl single ionic bond pairs) bond pairs with one sodium in the outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the NaCl Lewis structure. One electron bond pairs are shown as dots in the NaCl chemical structure, whereas one single bond contains two electrons. The outermost valence shell electrons of the NaCl molecule(bond pairs) are 2 as a result of the calculation. The total valence electron in a chlorine atom is 8.

So far, we’ve used 8 of the NaCl Lewis structure’s total 8 outermost valence shell electrons. Three lone pairs of electrons on the chlorine atom in the linear or tetrahedral geometry of the NaCl molecule.

Complete the middle NaCl atom stability and, if necessary, apply a covalent bond. The central chlorine atom undergoes octet stability(due to one single bond pair of electrons).

The core atom in the NaCl Lewis structure is chlorine, which is bonded to the one sodium atom by single bonds (one Na-Cl). With the help of one single bond, it already shares 8 electrons. As a result, the chlorine follows the octet rule and has 8 electrons surrounding it on the one terminal of the NaCl molecule’s linear or tetrahedral geometry.

How to calculate the formal charge on chlorine and sodium atoms in NaCl Lewis Structure?

Calculating formal charge on the chlorine of NaCl molecule:

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

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

The chlorine core atom (one single bond connected to one sodium atom) of the NaCl molecule has seven valence electrons, three lone pairs of electrons(six electrons), and 2 bonding pairing valence electrons. Put these values for the chlorine atom in the formula above.

Formal charge on chlorine atom of NaCl molecule = (7- 8-(0/2)) = -1

In the Lewis structure of NaCl, the formal charge on the central chlorine atom is -1 (negative charge).

Calculating formal charge on the sodium atom of NaCl molecule:

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

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

The sodium terminal atoms of the NaCl molecule have one valence electron, no lone pairs of electrons(zero electrons), and two bonding pairing valence electrons(single bond). Put these values for the sodium atom in the formula above.

Formal charge on sodium atom of NaCl molecule = (1- 0-(0/2)) =+1

In the Lewis structure of NaCl, the formal charge on the terminal sodium atom is +1 (positive charge).

Summary:

In this post, we discussed the method to construct the NaClr Lewis structure. First, the valence electrons are placed around the sodium atom and lose one electron. Then it becomes sodium positive ions. Second, place the valence electron on the chlorine atoms and the chlorine atom accepts one electron in its valence shell. Finally, when we combined the first and second steps. It gives NaCl Lewis structure. Need to remember that, if you follow the above-said method, you can construct molecular dot structure very easily.