1 / 11

Molecular Compounds

Learn about polar and nonpolar covalent bonds, how electronegativity affects polarity, and how to determine if a molecule is polar or nonpolar based on its shape and bond polarities. Explore examples and the concept of dipole moments.

gillett
Download Presentation

Molecular Compounds

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 Compounds Polarity

  2. Molecular Compounds • Polarity– is the difference between the electronegativity values for the two atoms sharing a pair of electrons. • The greater the difference, the more polar the bond is.

  3. Molecular Compounds • Nonpolar Covalent Bonds– this occurs when the two atoms sharing the electrons have the same electronegativity. • H2 Cl2 Br2 N2 • The electron pair is shared equally between the two atoms.

  4. Molecular Compounds • Polar Bonds - this occurs when the two atoms sharing the electrons have different electronegativity values. H-C N-O C-Cl • The electron pair is shared unequally between the two atoms. • This unequal sharing is shown by drawing an arrow towards the more electronegative atom

  5. Molecular Compounds Examples: d+ d- d+ d- C O C Cl d+ is a partial positive charge caused by the e- moving away from the atom d- is a partial negative charge caused by the e- moving toward the atom

  6. Molecular Compounds • A molecule can have polar bonds, yet still not be a polar molecule. • You must evaluate the bonds as they appear in the 3-D shape of the molecule.

  7. Molecular Compounds Example: CO2 O=C=O AX2 linear 180o Therefore, the pull of one bond cancels out the pull of the other bond. (tug-of-war; the middle doesn’t move) Each bond is polar, but the overall affect results in a nonpolar molecule

  8. Molecular Compounds • Example: CH4 H H - C - H H AX4 tetrahedral 109.5o Again, each bond is polar, yet overall, the effects cancel each other out. The molecule is nonpolar

  9. Molecular Compounds • Example: NH3 H ;; H - N - H AX3E trigonal pyramidal 109.5o Each bond is polar. In this case, the molecule is polar As the electrons are being drawn towards one end of the molecule. d- d+

  10. Molecular Compounds • It is the uneven distribution of electrons in a molecule that results in a dipole moment. • Example: • Compare the dipole moment in H2S to that of H2O

  11. Molecular Compounds H2SAX2E2 bent 109.5 H2O AX2E2 bent 109.5 • Because the H-S bond is less polar than the H-O bond, the dipole moment in H2S is weaker than the dipole moment in H2O

More Related