sp2 hybridisation structure of C2H4????

Dear Student, 

In ethene C₂H₄, each carbon uses its 2s and two 2p orbitals for hybridization resulting three sp² hybrid orbitals. The third  2p orbital remains unhybridized.

Following fig shows the how double bond occurs

Step 1- Atomic orbitals of C-atom in ground state

Step 2- Atomic orbitals of C-atom in excited state

Step 3- sp² hybridization in C-atom with three sp²hybride orbitals and one p unhybrid orbital

Step 4- The three sp² orbitals are shared by one C and two H atoms to give ethene molecule having C-C double bonds (one sigma and one pie)