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10.2: VSEPR

  • Page ID
    96591
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    Introduction:

    This part of the review goes over the use of Valence Shell Electron Repulsion Theory (VSEPR) to determine molecular geometries. You should review your general chemistry 1 notes. If they are not available, go to
    section 8.6: Molecular Geometries

    Worksheets

    Handout \(\PageIndex{1}\) : Overview of Structures:
    http://chemwiki.ucdavis.edu/@api/deki/files/60818/VESPR_Geometry_Handout.pdf T
    The above 3 page handout gives the basic VESPR geometries of table 2.1 (below), along with the hybrid orbitals (review section

    Handout \(\PageIndex{2}\) : VSEPR Worksheet
    http://chemwiki.ucdavis.edu/@api/deki/files/61155/vsepr2_Worksheet.pdf
    The above handout is a continuation of the exercise in section 10.1 Lewis Dot Structures.  You should fill out that handout first, and then use it while filling out this handout.

     

    Molecular Geometries

    Table 1 shows some examples of geometries with a central atom \(A\) is bonded to two or more \(X\) atoms. As indicated in several of the geometries below, non-bonding electrons can strongly influence the molecular geometry of the molecule. Note: "E" represent lone pairs of electrons

    Table \(\PageIndex{1}\) :
    6 5 4 3 2
    AX6
    ax6.gif
    octahedral
    AX5
    ax5.gif
    trigonal bipyramidal
    AX4
    ax4.gif
    tetrahedral
    AX3
    ax3.gif
    trigonal planar
    AX2
    linear_label.gif
    linear
    1 lone pair of electrons
    AX5E
    ax5e.gif
    square pyramidal
    AX4E
    ax4e.gif
    distorted tetrahedron
    AX3E
    ax3e.gif
    pyramidal
    AX2E
    ax2e.gif
    nonlinear
    AXE
    linear_label.gif
    linear
    2 lone pairs of electrons
    AX4E2
    ax4e2.gif
    square planar
    AX3E2
    ax3e2.gif
    T-shaped
    AX2E2
    ax2e2.gif
    bent
       

    These structures can generally be predicted, when A is a nonmetal, using the "valence-shell electron-pair repulsion model (VSEPR) discussed in the next section. This image table was borrowed from Paul Groves LibreText, and the rotating molecules were created by Robyn Rindge.

    Exercise \(\PageIndex{1}\)

    What is the molecular geometry of triiodide (I3-), which has two bonding and 3 lone pairs? (It is not in the above table)

    Answer

    Linear


    10.2: VSEPR is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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