These are the p molecular orbitals of ethylene. There are two carbon atoms with sp² hybridization and one 2p orbital with one electron each. These two orbital overlap and generate two molecular orbital. Click on each one to view molecular orbitals.

 

This is the lowest energy molecular orbital. There is a bonding interaction between the two 2p orbital and zero node. The orbital has two opposite lobes on the top and bottom of ethylene molecular plane. This is a bonding molecular orbital with two electron. This is the Highest Occupied Molecular Orbital or HOMO.

 

This is the highest energy p molecular orbital with one node and an antibonding interaction between two 2p orbital. This molecular orbital is empty and is the Lowest Unoccupied Molecular Orbital or LUMO.