Assume that the MOs of diatomics from the third row of the periodic table, such as P2, are analogous to those from the second row.
c. For the P2 molecule, how many electrons occupy the MO in the figure?

Verified step by step guidance

1. Determine the total number of valence electrons in a P2 molecule. Each phosphorus atom has 5 valence electrons, so for P2, there are 5 + 5 = 10 valence electrons.
2. Identify the molecular orbitals (MOs) that these electrons will occupy. For diatomic molecules like P2, the MOs are typically arranged in the order: \(\sigma_{2s}, \sigma^*_{2s}, \sigma_{2p_z}, \pi_{2p_x} = \pi_{2p_y}, \pi^*_{2p_x} = \pi^*_{2p_y}, \sigma^*_{2p_z}\).
3. Fill the MOs with the 10 valence electrons, starting from the lowest energy orbital and moving to higher energy orbitals. Each MO can hold a maximum of 2 electrons.
4. Assign electrons to the MOs: \(\sigma_{2s}\) gets 2 electrons, \(\sigma^*_{2s}\) gets 2 electrons, \(\sigma_{2p_z}\) gets 2 electrons, and \(\pi_{2p_x} = \pi_{2p_y}\) together get 4 electrons (2 in each \(\pi\) orbital).
5. Verify that all 10 electrons are accounted for and that the MOs are filled according to the Pauli exclusion principle and Hund's rule.

Key Concepts

Molecular Orbitals (MOs)

Molecular orbitals are formed by the combination of atomic orbitals when atoms bond together. In diatomic molecules, these MOs can be classified as bonding or antibonding, depending on whether they stabilize or destabilize the molecule. Understanding the arrangement and energy levels of these orbitals is crucial for determining how many electrons can occupy them.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom or molecule's orbitals. For diatomic molecules like P2, the total number of valence electrons from both atoms must be considered to determine how they fill the available molecular orbitals. This configuration helps predict the molecule's stability and magnetic properties.

Periodic Trends in Bonding

Periodic trends refer to the predictable patterns in elemental properties based on their position in the periodic table. For third-row elements like phosphorus, the bonding characteristics and molecular orbital behavior can be inferred from those of second-row elements, allowing for analogies in their molecular orbital diagrams. This understanding aids in predicting the electron occupancy in MOs for similar diatomic molecules.