Consider the molecular orbitals of the P2 molecule. Assume that the MOs of diatomics from the third row of the periodic table 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. Step 1: Identify the number of valence electrons in a single phosphorus (P) atom. Phosphorus is in group 15 of the periodic table, so it has 5 valence electrons.
2. Step 2: Determine the total number of valence electrons in the P2 molecule. Since there are two phosphorus atoms, multiply the number of valence electrons by 2.
3. Step 3: Draw the molecular orbital (MO) diagram for the P2 molecule. Since the MOs of diatomics from the third row are analogous to those from the second row, use the MO diagram for diatomic nitrogen (N2) as a reference.
4. Step 4: Fill the molecular orbitals with the total number of valence electrons, starting from the lowest energy level and following the Pauli exclusion principle and Hund's rule.
5. Step 5: Count the number of electrons in the molecular orbital shown in the figure. The figure represents a specific MO, and you need to determine how many of the total valence electrons occupy this particular MO.

Key Concepts

Molecular Orbitals (MOs)

Molecular orbitals are formed by the combination of atomic orbitals when atoms bond together. In diatomic molecules like P2, these orbitals can be bonding or antibonding, depending on the phase relationship of the combining atomic orbitals. Understanding the arrangement and energy levels of these MOs is crucial for predicting the electron configuration and stability of the molecule.

Electron Configuration in Diatomic Molecules

The electron configuration of diatomic molecules involves filling molecular orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle. For P2, which has a total of 12 valence electrons, these electrons will fill the MOs starting from the lowest energy level, influencing the molecule's bond order and magnetic properties.

Bond Order

Bond order is a measure of the number of chemical bonds between a pair of atoms and is calculated as half the difference between the number of bonding and antibonding electrons in a molecule. For P2, determining the bond order from the molecular orbital diagram helps assess the stability and strength of the bond, which is essential for understanding the molecule's behavior in chemical reactions.