Final answer:
The molecular orbital configurations of ions such as O₂²⁻, N₂²⁻, F₂, and Li₂⁻ determine their stability, relying on their electron configurations in bonding and antibonding orbitals. Stability is generally indicated by a positive bond order, which is calculated based on the difference between bonding and antibonding electron pairs.
Step-by-step explanation:
Molecular Orbital Configurations and Stability of Ions
To predict the valence electron molecular orbital configurations for various ions and determine their stability, we consider the molecular orbital (MO) theory, which provides a method for describing the electronic structure of diatomic molecules and ions. We specifically look at the valence electrons as they are involved in bonding and greatly affect molecular stability.
O₂²⁻ is the peroxide ion with two additional electrons in antibonding orbitals compared to the O₂ molecule, resulting in a weaker bond and a potentially less stable ion. N₂²⁻, with two electrons removed from bonding orbitals, has increased bond strength and can be more stable.
F₂ has all its valence electrons in bonding or nonbonding orbitals, making it relatively stable. Li₂⁻ will be an unstable ion due to its electron count leading to half-filled antibonding orbitals.
When discussing MO configurations, it is important to remember the bond order, which is the number of bonding electrons minus the number of antibonding electrons divided by two.
Stable species generally have a positive bond order, while those with a bond order of zero or negative are predicted to be unstable.