In ethene C2H4 , the carbon atoms are sp2 hybridized. This means that one 2s orbital and two 2p orbitals of the carbon atom mix to form three sp2 hybrid orbitals. These sp2 hybrid orbitals are arranged in a trigonal planar geometry around the carbon atom.Each carbon atom in ethene forms three sigma bonds: one with the other carbon atom and two with hydrogen atoms. These sigma bonds are formed by the overlap of the sp2 hybrid orbitals of the carbon atoms with the 1s orbitals of the hydrogen atoms and the sp2 hybrid orbitals of the other carbon atom.In addition to the sigma bonds, there is also a pi bond between the two carbon atoms in ethene. This pi bond is formed by the side-by-side overlap of the unhybridized 2p orbitals of the carbon atoms. The pi bond is weaker than the sigma bonds and is responsible for the double bond character in ethene.In summary, the sp2 hybrid orbitals in the carbon atoms of ethene contribute to the formation of three sigma bonds with other atoms, while the unhybridized 2p orbitals form a pi bond between the two carbon atoms, resulting in a double bond.