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C2H4 is the chemical formula of a colourless and flammable gas known as Ethylene. It is said to be a hydrocarbon that has two carbon atoms connected to it with a double bond. It is lighter than air. C2H4 is an example of sp² hybridization, meaning one s orbital, and two p orbitals are mixed to give three sp² orbitals. Here, one 2p orbital does not change, and it will help form a pi bond. Each of the sp² carbon atoms has a trigonal planar geometry and an angle of 120o between the bonds. As per VSEPR theory, C2H4 molecular geometry and electron geometry are the same, i.e. trigonal planar.
C2H4 Molecular Geometry Importance
Molecular structure defines the arrangement of atoms in a molecule or ion. In the case of C2H4 , each carbon in its molecule undergoes sp² hybridization, and the two hydrogens make the structure look like a two-dimensional triangular planar. The bonded pair of hydrogen attached to carbon repels each other, and as a result, the figure thus formed is a trigonal planar. Lewis structure helps to find out C2H4 molecular geometry as Lewis diagram determines the number of lone pairs and bond pairs a molecule comprises.
The A-X-N method can find out the C2H4 molecular geometry and bond angles. Here, the central atom is represented by ‘A’. In this case, A=1. The number of atoms that have bonded with the central atom is denoted by ‘X’. Here, the two carbon atoms are bonded, and both atoms have two hydrogen atoms attached to them. ‘N’ denotes the number of lone pairs attached to the central atom, and C2H4 has no lone pair, meaning N=0. So, we got AX3 for the C2H4 molecule by the A-X-N method. As the molecule does not have any lone pairs, we may ignore N. AX3 defines the shape of C2H4 as a Trigonal Planar with 120 degree bond angles.
C2H4 Molecular Geometry Questions
How to find out the C2H4 molecular geometry and bond angles?
The three steps to find out the C2H4 molecular geometry and bond angles are:
1. Firstly, discover the number of lone pairs that the central atom of C2H4 has.
Another term for a lone pair is unshared pair. In accordance with the Lewis structure of C2H4 , it is found that there is no lone pair present on the central atom.
We can also use the formula for the confirmation of lone pairs i.e.
L.P = (V.E – N.A)/2
L.P stands for the lone pair on the central atom, V.E stands for the Valence electron of that particular central atom, and N.A stands for the number of atoms attached to the central atom.
Valence electrons of carbon = 4. The atoms that are attached to the carbon atoms = 4
Therefore, Lone pair = (4 – 4)/2. So we got to know that the molecule has no lone pair.
2. Find out the hybridization of C2H4
To determine the C2H4 molecular geometry, it is required to find out the hybridization of C2H4 . The formula to find out hybridization is:- H = N.A. = L.P.
H stands for hybridization, N.A. stands for the number of atoms attached to the central atom, and L.P. stands for lone pairs on that particular atom. When we look at the Lewis dot structure of C2H4 , we find out that carbon is the central atom of the molecule, and each carbon atom is linked with three atoms, i.e. one carbon and two hydrogen atoms. In the earlier step, we found that it has 0 lone pairs, so we use that information here in this formula.
H = 3 + 0
The number of hybridization comes out to be three, which means it is an sp² hybridization.
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Conclusion
Ethylene is a colourless gas lighter than air and is also soluble in water. The chemical formula for Ethylene is C2H4 which means it has two carbon atoms and four hydrogen atoms. The two carbon atoms are linked to each other, and each atom is attached to two hydrogen atoms. C2H4 molecular geometry is a trigonal planar, and its electron geometry is also the same. The angle between the bonds is 120o. Also, the free rotation of the two carbon double bonds is restricted. We can take the help of Lewis’s structure to find out the molecular geometry as it defines the number of bond pairs and lone pairs that are contained in the molecule.
