Ethene (C2H4) lewis dot structure, molecular geometry, polar or non-polar, hybridization

Home  > Chemistry Article > C2H4 lewis structure and its molecular geometry

In this article, we will study ethene (C2H4) lewis structure, molecular geometry, hybridization, is it polar or non-polar, etc.

Ethene gas is lighter than air. It has a sweet odor and can cause an explosion. Also, it is not toxic but a simple asphyxiant.

Some properties of Ethene

• It is soluble in water.
• It has a molar mass of 28.054 g·mol−1.
• The density of C2H4 is 1.178 kg/m3.
• The ethene melting point is −169.2 °C and the boiling point is −103.7 °C.
• It can easily be ignited.
 Name of Molecule Ethene/Ethylene Chemical formula C2H4 Molecular geometry of C2H4 Trigonal planar Electron geometry of C2H4 Trigonal planar Hybridization Sp² Bond angle 120º Total Valence electron for C2H4 12 The formal charge of C2H4 0
Page Contents

How to draw lewis structure for C2H4?

C2H4 Lewis structure contains four C-H bonds and one double bond in between two carbon atoms. No lone pair is present on the central or outer atom in the lewis structure of C2H4.

The lewis dot structure of C2H4 is very easy to draw-

Some steps need to follow for drawing the C2H4 Lewis dot structure

1. Count total valence electron in C2H4

In the first step, we need to find its valence electron, For counting valence electrons in C2H4, you need to know the group number of atoms in the periodic table.

As carbon belongs to the 14th group in the periodic table, therefore it has 4 valence electrons. And hydrogen only needs one electron to complete its valence shell.

⇒ Carbon valence electrons = 4

⇒ Hydrogen valence electron = 1

∴ Total valence electrons available for C2H4 lewis structure = 4*2 + 1*4 = 12 valence electrons                             [∴ C2H4 has two carbon and 4 hydrogen atom]

2. Find the least electronegative atom and placed it at center

Does not matter in any lewis diagram if there is hydrogen present then it will go outside. So, Place carbon at the center in the lewis structure diagram, and hydrogen spaced evenly around it.

3. Connect carbon and hydrogen with a single bond

In this step, place both carbon atoms at the center and hydrogen spaced evenly around it. And connect them with the help of a single bond.

As you see in this structure, we used 5 single bond which contains 10 electrons for connecting hydrogen atoms to the central atom.

So, after using 10 electrons we are left with only 2 valence electrons. Because total valence electrons in C2H4 are 12.

4. Place remaining valence electrons starting from outer atom first

As hydrogen only needs 2 electrons to complete its octet shell. Look at the structure in the 3rd step, all hydrogen already got what they want.

So, placed these 2 electrons around the central atom.

After placing all valence electrons, we got to know that one carbon is still left to complete its octet rule.

5. Complete central atom octet and make covalent bond if necessary

As one carbon got only 6 electrons to share and it needs two more to complete its octet rule.

For overcoming this problem, convert the lone pair to covalent present on the right carbon in the 4th step structure of C2H4.

Ethene (C2H4) lewis structure

Now both carbons complete their octet rule by sharing 8 electrons.

So, we got our stable Ethylene or Ethene lewis structure.

What are the electron and molecular geometry of C2H4?

The molecular geometry of C2H4 is trigonal planar and its electron geometry is also trigonal planar according to VSEPR (Valence shell electron pair repulsion theory).

As each carbon in the C2H4 molecule has Sp² hybridization and with two hydrogens it makes the structure look like a triangular planar which is two-dimensional.

As you see in the above structure, bonded pair electron between hydrogen atoms tries to repel each other, as a result, they will push each other, hence, with the respect of each carbon(left and right), the shape will look like trigonal planar.

The bond angle of C2H4 is 120º. And there is no free rotation about a carbon-carbon double bond.

Each H–C–H bond angle is around 117.5º because the presence of a double bond in between carbon atoms shrinks the angle between the H–C–H bond from 120º to 117.5º.

C2H4 Lewis’s structure is very helpful to find Its molecular geometry because the lewis diagram helps us to determine how many bond pairs and lone pairs a molecule contains.

Let’s see how to find this.

Follow three steps to find C2H4 molecular geometry

1. Find the Number of lone pairs present on the central atom of the C2H4 Lewis structure

The lone pair is also called the unshared pair. According to the lewis structure of C2H4, there is no lone pair present on the central atom.

To confirm it you can also use the formula to find lone pairs.

L.P = (V.E. – N.A.)/2

where L.P. = Lone pair on the central atom

⇒ V.E. = valence electron of that central atom

⇒ N.A. = Number of atoms attached to that central atom

So, the valence electron of carbon is 4, and the number of atoms attached to the carbon(central atom) is also 4.

Hence L.P. = (4 – 4)/2

= 0 lone pair

2. Find hybridization number of C2H4

In this step, we need to determine the hybridization number of C2H4. So that we can use it to determine the molecular geometry of C2H4.

H = N.A. + L.P.

where H = hybridization number

⇒ N.A. = Number of atoms attached to the central atom

⇒ L.P. = lone pairs on that central atom

According to the C2H4 lewis dot structure, carbon is the central atom and each carbon is attached to three atoms( 1 Carbon + 2 Hydrogen).

Also lone pair present on the carbon is zero

So, H = 3 + 0

= 3 is the hybridization number for C2H4

Therefore hybridization of C2H4 is Sp²

Note: Each carbon in the C2H4 Lewis structure contains Sp² hybridization.

3. Use VSEPR theory or AXN method to determine C2H4 molecular geometry

According to the VSEPR chart, if any molecule contains zero lone pair and Sp² hybridization then the molecular and electron geometry of that molecule is trigonal planar.

C2H4 molecular geometry or Shape

AXN method is also very helpful to determine the molecular geometry of C2H4.

Let’s see how to use this method.

• A represents the central atom.
• X represents the bonded pairs of electrons to the central atom.
• N represents the lone pairs of electrons on the central atom

So, according to the C2H4 Lewis structure, carbon is the central atom that has 3 bonded pairs and 0 lone pairs of electrons.

Hence, we got the AX3 formula for C2H4. As per the VSEPR chart, if any molecule has an AX3 formula then the molecular and electron geometry of that molecule is Trigonal planar.

 Bonded atoms Lone pair Generic formula Hybridization Molecular geometry Electron geometry 1 0 AX S Linear Linear 2 0 AX2 Sp Linear Linear 1 1 AXN Sp Linear Linear 3 0 AX3 Sp² Trigonal planar Trigonal planar 2 1 AX2N Sp² Bent Trigonal planar 1 2 AXN2 Sp² Linear Trigonal planar 4 0 AX4 Sp³ Tetrahedral Tetrahedral 3 1 AX3N Sp³ Trigonal pyramid Tetrahedral 2 2 AX2N2 Sp³ Bent Tetrahedral 1 3 AXN3 Sp³ Linear Tetrahedral 3 2 AX3N2 Sp³d T-shaped Trigonal bipyramidal

Ethene polarity: Is C2H4 polar or non-polar?

Is C2H4 polar or non-polar? Obviously, ethene is a non-polar molecule because of its symmetrical shape and very minimal electronegativity difference between carbon and hydrogen.

Let’s see other factors which will clear the doubt regarding Is C2H4 polar or non-polar.

Three factors that indicate the polarity of C2H4

1. Electronegativity:

The electronegativity difference between carbon and hydrogen atoms is very low therefore electrons are attracted or shared almost equally by both atoms.

The electronegativity of Carbon is 2.55 and for hydrogen, it is 2.20. And the difference of electronegativity between carbon and hydrogen atoms is less than 0.4.

So, according to the Pauling scale if the electronegativity difference between atoms is less than 0.4, then that molecule is non-polar in nature.

Also, electronegativity is the tendency of an atom to attract an electron to itself. So, Carbon and hydrogen have almost the same tendency of pulling electrons.

Hence, electrons are equally shared between carbon and hydrogen making C2H4 non-polar in nature.

2. Dipole moment

The dipole moment is a measure of the strength of polarity between atoms. Obviously, the non-polar molecule has zero dipole moment because no positive and negative charge is induced in between the atoms.

So, if no charge is present between the atoms then dipole also cannot be generated.

In mathematical terms, we can express dipole moment as D = Q × R

Dipole moment formula =  charge on the atoms * the distance between them

3. Geometrical or molecular shape:

C2H4 has planar geometry because each carbon present in the C2H4 Lewis structure holds Sp² hybridization and with respect to each carbon, 2 hydrogen atoms make triangular geometry.

Also the presence of a double bond between the carbon atoms making it linear. And H–C–H bond in both sides (Left and Right) in the lewis structure of ethene is symmetrical and planar.

Hence all these factors show How C2H4 is non-polar in nature. I hope you got this very well.

What is the formal charge in the C2H4 Lewis structure and how to calculate it?

The formal charge of ethene shows which atom(Hydrogen and carbon) has more negative and positive charges present on it.

Formal charge = (Valence electrons – unbonded electrons – 1/2 bonded electrons)

We will calculate the formal charge on the Central atom which is carbon in the C2H4 Lewis structure.

⇒ Valence electron of carbon = 4

⇒ Bonding electrons = 8

⇒ Non-bonding electrons(Lone pairs) = 0

Now put these values in the given formula

∴ 4 – 0 – 8/2

= 0 formal charges on each carbon(Right and left carbon).

Uses of Ethylene

1. C2H4 is used in agriculture to force the ripening of fruits.
2. It is used as an anesthetic, a refrigerant, and in producing chemicals.
3. It is used to make films in the packaging.
4. Ethene is widely used in the process of polymerization.

FAQ

Why are the electron and molecular geometry of C2H4 is same?

As we discussed, the molecular geometry of C2H4 is trigonal planar but its electron geometry is also trigonal planar.

Because electron geometry considers bond pair and lone pair of electrons and molecular geometry consider only bonded pair of electron.

And lone pair is 0 according to the C2H4 dot diagram. So, electron geometry also considers only bonded pairs of electrons.

Hence electron geometry = molecular geometry of C2H4

How many shared pairs of electrons are in the lewis dot structure of C2H4?

As per the C2H4 Lewis structure, Four C–H sigma bonds are present and one C=C double bond(1 sigma + 1 pie bond).

It means four C–H bond has 8 shared pairs of electrons and C=C bond has 4 shared pairs of electrons.

Hence total shared pairs of electrons in the dot diagram of C2H4 is 12.

Why C2H4 lewis structure is planar and C2H6 is non-planar?

Each carbon in the C2H4 Lewis structure has Sp² hybridization and with two hydrogens it makes the structure look like a triangular planar which is two-dimensional.

Hence Ethene is planar.

Whereas C2H6 has Sp³ hybridization and its geometry is trigonal bipyramidal which is 3-dimensional.

Hence C2H6 is non-planar.

Summary

It’s time for the quick revision of the Ethene (C2H4) Lewis structure, molecular geometry, and other aspects which we have discussed in this article.

• The bond angle of ethylene is 120º.
• The hybridization of C2H4 is Sp².
• The molecular geometry or shape of C2H4 is trigonal planar.
• Ethene lewis’s structure is made up of two carbon and four hydrogens, the carbon atoms at the middle position and the hydrogen atom at the surrounding position.
• The total valence electrons available for the C2H4 lewis dot structure is 12.
• C2H4 is non-polar in nature.
Subscribe to Blog via Email

Join 2 other subscribers

Share it...