Which is the correct Lewis structure of C2H4

Which is the correct Lewis structure of C2H4

The Correct Answer and Explanation is :

The correct Lewis structure of ethylene (C₂H₄) can be represented as follows:

    H       H
     \     /
      C = C
     /     \
    H       H

Explanation:

1. Counting Valence Electrons: Ethylene (C₂H₄) consists of two carbon atoms and four hydrogen atoms. Carbon (C) has four valence electrons, and hydrogen (H) has one valence electron. Therefore, the total number of valence electrons in C₂H₄ is:
   [
   2 \times 4 \, (C) + 4 \times 1 \, (H) = 8 + 4 = 12 \, \text{valence electrons}
   ]
2. Selecting the Central Atoms: In C₂H₄, the two carbon atoms will be connected to each other, as they will share electrons to form bonds. Each carbon atom will also be bonded to two hydrogen atoms.
3. Constructing the Bonds: We start by placing a single bond (a pair of electrons) between the two carbon atoms:
   [
   C – C
   ]
   However, to satisfy the octet rule (each carbon atom needs eight electrons around it), we place a double bond between the carbon atoms:
   [
   C = C
   ]
   Now, each carbon atom has four electrons from the double bond.
4. Adding Hydrogen Atoms: Each carbon atom can form two additional single bonds with hydrogen atoms. We can attach two hydrogen atoms to each carbon:
   [
   H – C = C – H
   ]
   This structure satisfies the valence requirements: each hydrogen has two electrons (a full valence shell), and each carbon has eight electrons.
5. Final Structure: The resulting structure shows each carbon atom sharing four electrons with the other carbon atom and forming single bonds with two hydrogen atoms. Thus, the final Lewis structure of ethylene (C₂H₄) is correctly depicted with a double bond between the carbon atoms and single bonds to the hydrogen atoms, fulfilling the octet rule for the carbons and the duet rule for the hydrogens.

This structure helps in understanding the molecular geometry and reactivity of ethylene, making it an essential model in organic chemistry.