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Molecular Shapes (VSEPR): Flashcards

Revise electron domains, VSEPR shapes, bond angles and molecular polarity.

10 cardsIntermediate

10 cards

  1. Question
    What does VSEPR stand for?
    Answer

    Valence-shell electron-pair repulsion.

  2. Question
    What counts as one electron domain?
    Answer

    A lone pair, or a bond to another atom. Single, double and triple bonds each count as one domain.

  3. Question
    Shape and bond angle with 4 domains and 0 lone pairs?
    Answer

    Tetrahedral, 109.5° (e.g. CHX4\ce{CH4})

  4. Question
    Shape of NHX3\ce{NH3}?
    Answer

    Trigonal pyramidal, about 107° (4 domains, 1 lone pair)

  5. Question
    Shape of HX2O\ce{H2O}?
    Answer

    Bent, about 104.5° (4 domains, 2 lone pairs)

  6. Question
    Shape and bond angle with 3 domains and 0 lone pairs?
    Answer

    Trigonal planar, 120° (e.g. BFX3\ce{BF3})

  7. Question
    Why do lone pairs make bond angles smaller?
    Answer

    Lone pairs repel more strongly than bonding pairs, pushing the bonds closer together.

  8. Question
    Why is COX2\ce{CO2} nonpolar even though C=O bonds are polar?
    Answer

    It is linear, so the two bond polarities point in opposite directions and cancel.

  9. Question
    Shape of SFX6\ce{SF6}?
    Answer

    Octahedral, 90° (6 domains, 0 lone pairs)

  10. Question
    Shape of PClX5\ce{PCl5}?
    Answer

    Trigonal bipyramidal, 90° and 120° (5 domains, 0 lone pairs)