2.2 Quiz

Formal charge

• Valence electrons-electrons in lone pairs-# of bonds

• why sulfur and phosphorus are exceptions

• because they can surpass the octet rule; this is because they have empty d orbitals that can be filled with extra electrons, giving rise to the possibility of an expanded octet

Resonance structures

• molecular/ionic compounds with more than 1 possible lewis structure

• linear molecular geometry

• if there are 2 atoms bonded to the central atom and zero lone pairs

  • 180 degrees

• linear molecular geometry

• if there are only 2 atoms; can’t make a shape

  • 180 degrees

• bent molecular geometry

• if there are 2 atoms bonded to the central atom and one lone pair

  • a little <109.5 degrees

• bent molecular geometry

• if there are 2 atoms bonded to the central atom and 2 lone pairs

  • a little <109.5 degrees

• trigonal planar molecular geometry

• if there are 3 atoms bonded to the central atom and 0 lone pairs

  • 120 degrees

• trigonal pyramidal molecular geometry

• if there are 3 atoms bonded to the central atom and 1 lone pair

  • a little <109.5 degrees

• tetrahedral molecular geometry

• if there are 4 atoms bonded to the central atom and 0 lone pairs

  • 109.5 degrees

• london dispersion intermolecular forces

• in all molecules

• dipole-dipole intermolecular forces

• in polar molecules

• hydrogen bonding intermolecular forces

• in polar molecules with H-F, H-O, H-N bonds

• compound is nonpolar if

• the central atom has 0 lone pairs

• all atoms around central atom are the same

• dipole moments

• they point toward the most electronegative molecules

  • bond polarity is toward the more electronative atom

  • molecular polarity is the overall dipole moment

• If the electronegativity is

  • <0.4, it is

nonpolar

• If the electronegativity is

  • 0.4-1.7, it is

polar

• If the electronegativity is

  • >1.7, it is

ionic