Molecular Orbital Theory Learning Objectives

Chapter 5 / Learning Objectives

• Generate Molecular Orbitals from Atomic Orbitals

  • Understand the interaction between atomic orbitals to create molecular orbitals.

• Identify and Label Molecular Orbitals

  • Molecular orbitals can be classified based on several parameters:

  • Types:

    • $ ext{σ (sigma)}$ orbitals

    • $ ext{π (pi)}$ orbitals

    • $ ext{δ (delta)}$ orbitals

  • Bonding Nature:

    • Bonding orbitals

    • Anti-bonding orbitals

    • Non-bonding orbitals

  • Parity:

    • Gerade (g) - symmetric with respect to inversion (if diatomic)

    • Ungerade (u) - asymmetric with respect to inversion (if diatomic)

• Identify Coefficients in Linear Combinations of Atomic Orbitals (LCAO)

  • Importance of understanding the sign of coefficients, which determines the contributions of atomic orbitals in the formation of molecular orbitals.

• Construct Molecular Orbital Diagrams

  • Ability to construct diagrams for:

  • Homonuclear diatomic molecules

  • Heteronuclear diatomic molecules

  • Ions

• Analyze s-p Mixing in Homonuclear Diatomic Molecules

  • Determine the presence or absence of mixing between s and p orbitals, which can influence molecular orbital energy levels.

• Determine Bond Order and Unpaired Electrons

  • Bond order is calculated using the formula:
    ext{Bond Order} = \frac{(Nb - Na)}{2}
    where $Nb$ = number of bonding electrons and $Na$ = number of anti-bonding electrons.

  • Count the number of unpaired electrons, vital for determining magnetic properties of the molecule.

• Generate Group and Molecular Orbitals for Larger Molecules or Polyatomic Ions

  • For larger systems:

  • Generate Group Orbitals:

    • Form from atomic orbitals located on outer atoms.

  • Interacting with Central Atom:

    • Combine group orbitals with atomic orbitals on the central atom to form overall molecular orbitals.