Here's an explanation:
1. Carbon Hybridization in Ethylene:
- Each carbon atom in ethylene undergoes sp2 hybridization, which involves the mixing of one 2s orbital and two 2p orbitals. This hybridization results in the formation of three equivalent sp2 hybrid orbitals arranged in a trigonal planar geometry.
- The remaining 2p orbital on each carbon atom remains unhybridized and is perpendicular to the plane of the sp2 hybrid orbitals.
2. Sigma Bond Formation:
- The sigma bond between C2 and H is formed by the overlap of one sp2 hybrid orbital from C2 and the s orbital of H.
- The sp2 hybrid orbital on C2 extends in the direction of the hydrogen atom, and the s orbital of H is spherically symmetrical. When these orbitals overlap along the internuclear axis, they form a strong sigma bond, holding the C2 and H atoms together.
This sp2-s overlap results in a cylindrical electron density region between the C2 and H atoms, providing a high degree of electron sharing and bonding. The sigma bond between C2 and H is crucial for the stability and structural integrity of the ethylene molecule.
In summary, the sigma bond between C2 and H in ethylene is formed by the overlap of an sp2 hybrid orbital from C2 and an s orbital from H. This overlap creates a strong cylindrical electron density region, holding the two atoms together.
