Question

Is there a specific reason why the energy of the σ2pz orbital varies relative to the π2px and π2py orbitals, depending on the atomic number of the atom?

Answer 1

The energy differences between the σ2pz, π2px, and π2py orbitals are influenced by factors such as nuclear charge and screening effect.

Step-by-step explanation:

The energy levels of the atomic orbitals depend on several factors, including the nuclear charge and the shielding effect. In the case of the σ2pz, π2px, and π2py orbitals, the energy differences arise due to the increasing nuclear charge and poor screening of the 2s electrons by the 2p electrons.

As we move across the periodic table from Li₂ to F₂, the nuclear charge increases, which leads to a larger energy gap between the ns and np atomic orbitals. This causes the energy of the σ2pz orbital to increase relative to the π2px and π2py orbitals.

Additionally, the bonding interaction between the 2s and 2pz orbitals is most favorable when the two orbitals have similar energies, which further influences the relative energies of the orbitals.