Two chlorine atoms make up a chlorine molecule. It’s a yellow gas with a strong odour at room temperature. Its density is high (3.2 g/mL).
The pH of the molecule is nearly neutral (pH=7.4). It is water soluble to a degree.
The boiling and melting points of molecular chlorine are respectively 239.11K and 171.6K. Because the link is created by the sharing of electrons, Cl2 is a covalent molecule.
We will learn about Lewis Structure, geometry, hybridization, and polarity of molecular chlorine in this article.
Lewis Structure of Cl2
The Lewis Structure is a basic representation of a molecule’s valence shell electrons. It describes how electrons in a molecule are arranged around specific atoms.
Because electrons are represented by dots in this form, it’s also known as electron dot structures.
It does not adequately explain geometry or bond formation, and it is not used for these purposes. The best Lewis structure is one that satisfies the octet rule and formal charges.
The Rule of the Octet
Noble gases are inert and stable substances. Because all components like to remain stable, achieving a noble gas-like structure is one of the driving forces for bond formation.
The configuration of all elements prefers to be similar to that of noble gases in the main group.
Because noble gases (except He) contain eight electrons in their valence shell, atoms prefer to have eight. The octet rule is a result of this.
It’s a purely theoretical idea. If all the electrons in a chemical bond are shared evenly, it indicates the charge on an atom.
A neutral molecule does not necessarily mean that all of its atoms are also neutral. On the constituent atoms, there is the possibility of equal and opposing charges.
It is calculated using the formula below.
(valence electrons in the isolated state of a neutral atom) – (non-bonding valence electrons on the atom) = formal charge (number of bonds formed by atom)
Drawing the Lewis Structure of Cl2 in Steps
- Count the total number of electrons in the valence shell of the molecule.
This is accomplished by adding all of the constituent atoms’ valence shell electrons.
Atomic Number Atomic Number Atomic Number Atomic Number Atomic Number Atomic Number Atom
According to group number, valence electrons
Configuration of electronic devices (E.C.)
E.C.’s Valence Shell
E.C.’s valence electrons
Cl 17 17 7 (two)
n=3 1s2 2s2 2p6 3s2 3p5
The total number of electrons in the valence shell is 7*2=14.
The Chlorine atom’s Lewis dot structure is as follows:
Out of the constituent atoms, the central atom is meant to be the least electronegative.
The electron density of the core atom is meant to be shared by all other atoms. Chlorine is a two-dimensional molecule. Both atoms are identical.
In a diatomic molecule, there is no need to assign a central atom because it is always linear.
- Sketch out a skeleton diagram.
In this phase, we must properly arrange the constituent atoms.
- Arrange the valence electrons around the symbol of the element.
Bond formation is used to put the entire valence shell electrons (calculated in step 1).
- Form bonds to complete the octet of atoms.
In the solitary state, each Cl contains seven valence electrons. To have a fully filled valence shell arrangement, each Cl shares one electron with another Cl.
- Determine all atoms’ formal charges.
This chemical has a net charge of zero. As a result, the total formal charge on three atoms should equal zero.
Number of valences in total
In a free atom, there are electrons.
Number of lone pairs in total (total number of bonding pairs)
Cl1 7 3 8*0.5=4
Cl2 7 3 8*0.5=4
As a result, the Lewis structure developed in step 5 is the best for Cl2.
The following video will help you better grasp the procedure for drawing the Lewis structure of chlorine molecules.
The goal of Lewis structure is not to predict geometries. VSEPR theory may predict the geometries and forms of compounds.
The valence shell electron pair repulsion theory is abbreviated as VSEPR.
The VSEPR theory states that
• The valence electron pairs reject each other, causing instability; therefore, the repulsions between them must be reduced to make the electron arrangement stable.
• As a result, electrons align themselves with the least amount of repulsion and the greatest distance between them.
• The molecule geometry is determined by the stable arrangement of atoms’ valence electron pairs.
Bonding pairs of electrons (bp) are valence shell electrons that are involved in bonding, while lone pairs of electrons are valence shell electrons that are not involved in bonding (lp).
A diatomic compound’s shape is always linear, hence there’s no need to use diverse theories to forecast its shape.
The molecular geometry, on the other hand, may or may not be the same as the shape. The orientation of the lone pair of electrons in relation to the bonded pair of electrons is determined by the geometry.
How to Use VSEPR to Predict Cl2 Geometry
- Determine A by counting the number of valence shell electrons on the centre atom (arbitrary variable)
There is no centre atom in the case of Cl2.
We chose the less electronegative element to be the centre atom when there is no central atom. Both atoms are the same in this case.
On any Cl, we can count the valence shell electrons. Cl has a valence electron count of seven. (Shown in step 1 of the Lewis structure drawing)
- Determine the number of side atoms and multiply by B. (arbitrary variable).
There is only one side atom (chlorine) in Cl2, and B=1.
- If the compound is charged, deduct the charge from B for positively charged compounds and add the charge to B for negatively charged compounds if the compound is charged. For neutral substances, this step might be skipped.
There is no charge contribution in Cl2, and B=1 is the only value.
- Add the contributions of side atoms and charge to the core atom’s contribution, i.e. A+B.
A+B=8 for Cl2.
- Multiply A+B by 2 to get the total number of electron pairs influencing the form.
There are four electron pairs in Cl2.
- Separate the total electron pairs into bonding and non-bonding electron pairs. The number of side atoms equals the number of bonding electron pairs.
There is only one side atom in Cl2. As a result, there are three non-bonding electron pairs and one bonding electron pair.
The following table can be used to forecast geometry and shape based on this information. The form of an electron is linear and its geometry is tetrahedral.
The result is a precise form.
Because there is no core atom, VSEPR theory describes the geometry of side atoms in relation to the central atom. Cl2 has a linear geometry and shape, according to us.
Hybridization of Cl2
Hybridization is a unique idea that explains the geometry and bonding of several polyatomic covalent compounds.
The mixing of atomic orbitals to generate equivalent hybrid orbitals is known as hybridization. It is concerned with energy redistribution.
It is impossible to blend all atomic orbitals. Hybrid orbitals can only be formed when orbitals with identical shapes, sizes, and energies mix.
One 3s and two 3p orbitals, for example, can be merged to generate sp2 hybrid orbitals, while 2p and 6d cannot.
The operations are simply carried out on the wavefunction of orbitals; there is no literal mixing of orbitals. Hybridization does not occur in all molecules, as it does in AsH3.
What is the best way to look for hybridization?
Subscripts 1 and 2 denote the first and second chlorine atoms, respectively.
The Hybridization Calculation Trick
The total electron pairs, which we estimated using VSEPR to forecast geometry, can also be used to predict hybridization.
In the case of Cl2, the entire domain is 4.
Hybridization is sp3 for steric number 4 according to the table.
Polarity of Cl2
The existence or absence of a net dipole moment determines a compound’s polarity. In turn, the net dipole moment is determined by-
• Individual bond dipole moments
• The electronegativities of the constituent atoms differ.
• Compound geometry and symmetry
There is only one Cl-Cl link in molecule Cl2. Cl has an electronegativity of 3.16.
Because the electronegativity difference is zero, the Cl-Cl bond is nonpolar. The bond’s dipole moment turns out to be zero.
A non-polar bond in a diatomic molecule implies a non-polar molecule.
Chlorine gas preparation
Using metal oxide to heat concentrated HCl
Manganese chloride and chlorine gas are generated when manganese dioxide interacts with strong HCl.
MnO2 + HCl —-> MnCl2 + Cl2 + 2H2O
• Used in wastewater treatment as a disinfectant.
• To keep stink at bay
• The use of chemical weapons in battle
• Paper and paper products manufacturing
• Pesticide manufacturing
• Production of PVC and CFCs
• Bleaching solution
• An oxidising agent is a substance that oxidises other substances.
• Au and Pt extraction
• Chlorine gas is made up of two atoms.
· One covalent link connects both chlorine atoms.
• The octet rule and formal charge on the constituent atoms are satisfied by the Lewis structure depicted in the preceding section.
• It’s a molecule with a straight line.
• Cl2 has been hybridised with sp3.
• It’s a covalent and non-polar molecule.
• The gas can be used in a variety of fields.
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