1 / 23

Understanding Molecular Structure and Polarity

Learn about molecular structure, molecular geometry, and VSEPR theory. Discover the different shapes of molecules and how to determine their polarity.

marthabecker
Télécharger la présentation

Understanding Molecular Structure and Polarity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Molecular Structure Molecular Geometry

  2. A. VSEPR Theory • Valence Shell Electron Pair Repulsion Theory • Electron pairs orient themselves so that valence electrons are as far apart as possible

  3. Lone pairs repel more strongly than bonding pairs!!! A. VSEPR Theory • Types of e- Pairs • Bonding pairs - form bonds • Lone pairs - nonbonding e-

  4. Bond Angle A. VSEPR Theory • Lone pairs reduce the bond angle between atoms.

  5. Know the 8 common shapes & their bond angles! B. Determining Molecular Shape • Draw the Lewis Diagram. • Count up e- pairs on central atom. • double/triple bonds = ONE pair • Shape is determined by the # of bonding pairs and lone pairs.

  6. BeH2 C. Common Molecular Shapes 2 total electron pairs *2 bonding pairs *0 lone pairs Note: Beryllium does not follow the octet rule. Beryllium is complete with 4 valence electrons LINEAR 180°

  7. BF3 C. Common Molecular Shapes 3 total electron pairs *3 bonding pairs *0 lone pairs TRIGONAL PLANAR 120° Note: Boron is also an exception to the octet rule. Boron is complete with 6 valence electrons

  8. SO2 C. Common Molecular Shapes 3 total pairs *2 bonding pairs *1 lone pair BENT <120°

  9. CH4 C. Common Molecular Shapes 4 total pairs *4 bonding pairs *0 lone pairs TETRAHEDRAL 109.5°

  10. NH3 C. Common Molecular Shapes 4 total pairs *3 bonding pairs *1 lone pair TRIGONAL PYRAMIDAL 107°

  11. H2O C. Common Molecular Shapes 4 total pairs *2 bonding pairs *2 lone pairs BENT 104.5°

  12. PCl5 C. Common Molecular Shapes 5 total pairs *5 bonding pairs *0 lone TRIGONAL BIPYRAMIDAL 120°/90°

  13. SF6 C. Common Molecular Shapes 6 total pairs *6 bonding pairs *0 lone pairs OCTAHEDRAL 90°

  14. F P F F D. Examples • PF3 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107°

  15. OCO D. Examples • CO2 2 total 2 bonding pairs 0 lone LINEAR 180°

  16. Molecular Structure Molecular Polarity

  17. Molecular Polarity • Polar Molecule: Molecule that has a partially positive end and a partially negative end. (It has electrical poles) • There is an uneven distribution of electrons in the molecule

  18. + - H Cl A. Dipole Moment • Direction of the polar bond in a molecule. • Arrow points toward the more electronegative atom.

  19. B. Determining Molecular Polarity • Depends on: • dipole moments • molecular shape

  20. F BF3 B F F B. Determining Molecular Polarity • Nonpolar Molecules • Dipole moments are symmetrical and cancel out.

  21. O net dipole moment H2O H H B. Determining Molecular Polarity • Polar Molecules • Dipole moments are asymmetrical and don’t cancel . .. ..

  22. B. Determining Molecular Polarity • Polar molecules have... • asymmetrical shape (lone pairs) or • asymmetrical atoms (attached atoms are different)

  23. B. Determining Molecular Polarity • Nonpolar Molecules have… • No lone pairs • All attached atoms are the same

More Related