Question

study the following sketch of a molecular orbital (mo) in a homonuclear diatomic molecule. this mo was formed by combining one 2s 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? bonding antibonding what is the energy of this mo, compared to the energy of a 1s orbital on one of the separate atoms? higher lower the same not enough information to decide

Explanation:

Step1: Identify the symbol

When two 2s atomic orbitals combine in a homonuclear diatomic molecule, the resulting bonding molecular - orbital is $\sigma_{2s}$ and the antibonding is $\sigma_{2s}^*$. Since the sketch shows a bonding - like pattern (no node between the nuclei), the symbol is $\sigma_{2s}$.

Step2: Determine bonding or antibonding

In a bonding molecular orbital, the electron density is concentrated between the two nuclei. In an antibonding molecular orbital, there is a node between the nuclei. Since there is no node between the nuclei in the given sketch, it is a bonding MO.

Step3: Compare energy

A 2s atomic orbital has higher energy than a 1s atomic orbital. A bonding molecular orbital formed from 2s atomic orbitals has lower energy than the 2s atomic orbitals from which it is formed, but still higher energy than a 1s atomic orbital. So the energy of this $\sigma_{2s}$ MO is higher than the energy of a 1s orbital on one of the separate atoms.

Answer:

Question	Answer
Is this a bonding or antibonding MO?	bonding
What is the energy of this MO, compared to the energy of a 1s orbital on one of the separate atoms?	higher