Using the molecular orbital energy ordering for second-row homonuclear diatomic molecules in which the π_2p orbitals lie at higher energy than the σ_2p, draw MO energy diagrams and predict the bond order in a molecule or ion with each number of total valence electrons. Will the molecule or ion be diamagnetic or paramagnetic? a. 10

Verified step by step guidance

1. Identify the second-row homonuclear diatomic molecule with 10 valence electrons. This could be a molecule like \( \text{N}_2 \).
2. Draw the molecular orbital (MO) energy diagram for the molecule. For second-row diatomic molecules, the order of orbitals is: \( \sigma_{1s} \), \( \sigma^*_{1s} \), \( \sigma_{2s} \), \( \sigma^*_{2s} \), \( \sigma_{2p} \), \( \pi_{2p} \), \( \pi^*_{2p} \), \( \sigma^*_{2p} \).
3. Fill the molecular orbitals with the 10 valence electrons, starting from the lowest energy orbital and moving upwards, following the Pauli exclusion principle and Hund's rule.
4. Calculate the bond order using the formula: \( \text{Bond Order} = \frac{1}{2} (\text{Number of bonding electrons} - \text{Number of antibonding electrons}) \).
5. Determine if the molecule is diamagnetic or paramagnetic by checking if all electrons are paired (diamagnetic) or if there are unpaired electrons (paramagnetic).

Key Concepts

Molecular Orbital Theory

Molecular Orbital (MO) Theory describes how atomic orbitals combine to form molecular orbitals that can be occupied by electrons. In diatomic molecules, these MOs can be bonding or antibonding, influencing the molecule's stability and properties. The energy levels of these orbitals determine the arrangement of electrons and the overall electronic structure of the molecule.

Bond Order

Bond order is a measure of the number of chemical bonds between a pair of atoms, calculated as the difference between the number of bonding and antibonding electrons divided by two. A higher bond order indicates a stronger bond and greater stability. For example, a bond order of 1 corresponds to a single bond, while a bond order of 2 corresponds to a double bond.

Magnetism in Molecules

The magnetic properties of a molecule, whether it is diamagnetic or paramagnetic, depend on the presence of unpaired electrons. Diamagnetic molecules have all electrons paired and are not attracted to a magnetic field, while paramagnetic molecules contain unpaired electrons and are attracted to magnetic fields. This property can be predicted from the molecular orbital diagram by examining the occupancy of the MOs.