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Topic F: Molecular Structure

  • Page ID
    170026
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    Learning Objectives

    WHAT YOU SHOULD BE ABLE TO DO WHEN YOU HAVE FINISHED THIS TOPIC:

    General Covalent Bonding Concepts

    1. Understand the relationship between potential energy and internuclear distance.
    2. Understand a covalent bond in terms of potential energy.
    3. Recognize that there are two models used to describe covalent bonding: (1) valence bond theory and (2) molecular orbital theory.

    Localized Electron Model of Covalent Bonding

    1. Draw reasonable Lewis structures for small molecules and common polyatomic ions.
    2. Determine bond order.
    3. Determine bond polarity.
    4. Apply the concept of bond energies to estimate \(\Delta\)H for any reaction.
    5. Understand the relationship between bond order, bond distance, and bond energy.
    6. Use VSEPR Theory to predict the 3D molecular geometry.
    7. Determine if a molecule is polar.
    8. Use resonance structures to show electron delocalization. Use formal charges to determine major and minor resonance contributors.
    9. Use atomic orbital overlap to model a covalent bond. (Valence Bond Theory)
    10. Use orbital hybridization to rationalize orbital geometry with the observed bond angles.
    11. Identify and describe a sigma bond and a pi bond in terms of orbital overlap.
    12. Overall, predict the following for a given Lewis structure:
    • The molecular geometry for a central bonding atom, including typical bond angles.
    • Whether the molecular geometry is likely to be distorted.
    • The orbital geometry and corresponding orbital hybridization (sp, sp2, sp3, etc.) that will align with the bond geometry for a central bonding atom.
    • Whether or not the molecule is polar.

    Delocalized Electron Model of Covalent Bonding

    1. Use molecular orbitals to model a covalent bond. (Molecule Orbital Theory)
    2. Use MO energy diagrams to determine bond order and magnetic properties of a molecule.
    3. Draw sketches of the molecular orbitals for diatomic molecules that are formed from linear combinations of two atomic orbitals, and identify each as bonding or antibonding.


    Topic F: Molecular Structure is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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