Consider the H2+ ion. (f) Which of the following statements about part (e) is correct: (i) The light excites an electron from a bonding orbital to an antibonding orbital, (ii) The light excites an electron from an antibonding orbital to a bonding orbital, or (iii) In the excited state there are more bonding electrons than antibonding electrons?

Key Concepts

Molecular Orbitals

Molecular orbitals are formed by the combination of atomic orbitals when atoms bond together. In diatomic molecules like H2+, electrons occupy these orbitals, which can be classified as bonding (lower energy, stabilizing) or antibonding (higher energy, destabilizing). Understanding the distribution of electrons in these orbitals is crucial for predicting the behavior of molecules when they absorb light.

Excitation of Electrons

When a molecule absorbs light, it can provide enough energy to excite an electron from a lower energy state (such as a bonding orbital) to a higher energy state (such as an antibonding orbital). This process alters the electron configuration of the molecule, which can affect its stability and reactivity. The specific transitions depend on the energy levels of the molecular orbitals involved.

Bonding vs. Antibonding Electrons

In a molecular ion like H2+, the balance between bonding and antibonding electrons determines the stability of the molecule. Bonding electrons contribute to the attraction between nuclei, while antibonding electrons can weaken this attraction. Analyzing the number of electrons in each type of orbital is essential for understanding the overall bond order and stability of the ion in its excited state.