Question

study the following sketch of a molecular orbital (mo) in a homonuclear diatomic molecule. this mo was formed by combining one 2p atomic orbital from each atom. the dark dots in this sketch are the nuclei. now use the sketch to complete the table below. write the symbol for this mo. is this a bonding or antibonding mo? what is the energy of this mo, compared to the energy of a 2p orbital on one of the separate atoms?

Explanation:

Step1: Identify the MO type

When two 2p atomic orbitals combine side - on, they form a $\pi$ molecular orbital. The sketch shows a side - on combination, so the symbol is $\pi$.

Step2: Determine bonding or antibonding

In a bonding $\pi$ molecular orbital, the electron density is between the nuclei. In an antibonding $\pi$ molecular orbital, there is a node (region of zero electron density) between the nuclei. The given sketch shows a node between the nuclei, so it is an antibonding MO.

Step3: Compare energy

Antibonding molecular orbitals have higher energy than the atomic orbitals from which they are formed. So the energy of this $\pi^*$ MO is higher than the energy of a 2p orbital on one of the separate atoms.

Answer:

Property	Answer
Is this a bonding or antibonding MO?	antibonding
What is the energy of this MO, compared to the energy of a 2p orbital on one of the separate atoms?	higher