SUMMATIVE TEST 2 REVIEW P1

• STUDY THE IMAGE

  
• ZERO LONE PAIRS ON CENTRAL ATOM

  
  

  LINEAR- AX2

  TRIGONAL PLANAR - AX3

  TETRAHEDRAL - AX4

  TRIGONAL BIPYRAMIDAL - AX5

  OCTAHEDRAL - AX6
• 1 LONE PAIR ON CENTRAL ATOM

  BENT - AX2E

  TRIGONAL PYRAMIDAL - AX3E

  SEESAW- AX4E

  SQUARE PYRAMIDAL - AX5E
• 2 lone pairs on central atom

  BENT - AX2E2

  T-SHAPED - AX3E2

  SQUARE PLANAR - AX4E2
• 3 LONE PAIRS ON CENTRAL ATOM

  LINEAR AX2E3
• Valence Shell Electron Pair Repulsion Theory (VSEPR) is a model that describes the geometry of molecules.
• VSEPR THEORY

  • used to predict the shape of the molecules from the electron pairs surrounding the central atom.
  • used to predict the 3-molecular geometry
• VSEPR THEORY

  > Electron pair stay far from each other as possible to MINIMIZE REPULSION

  
  

  >Molecular shape is determined by the number of BOND PAIRS

  
  

  >Treating multiple bonds as SINGLE BONDS.
• A-X-E METHOD

  A= central atom

  X= another atom is BONDED to the CENTRAL ATOM

  E= LONE PAIRS OF CENTRAL ATOM
• STERIC NUMBER

  • Total number of atoms bonded to a central atom
• FORMULA FOR STERIC NUMBER

  Steric number= Lone pair of Central atom + Number of atoms bonded to the electron (counted as one)
• Molecular Polarity

  • Distribution of electrical charge over the atoms joined by the bond
• Molecular Polarity

  • Distribution of electrical charge over the atoms joined by the bond
  • It relates to other physical properties ( boiling point, surface tension and etc.)
• > Two electrically charged regions, a molecule with two poles is called a DIPOLE.

  >Resulting from the unequal distribution of electron

  > DELTA (δ)- electric charge
• Negative Polarity- most electrons

  Positive Polarity- least electrons
• Two Factors to determine the polarity of a molecule

  • VSEPR MODEL
  • ELECTRONEGATIVITY
• MOLECULAR GEOMETRY (VSEPR MODEL)

  
  

  >Polar Molecule<

  • ASYMMETRIC
  • Containing LONE PAIRS on the central atom
  • Having DIFFERENT atoms BONDED
• >NON-POLAR MOLECULE<

  • SYMMETRIC all sides around the central atom
  • IDENTICAL-BONDED to the same element with unpaired electrons
  • no lone pair
• Electronegativity

  • tendency of an atom to attract electrons to itself
• LINUS PAULING SCALE

  0<0.4 = Pure covalent/ Non-polar covalent bond

  0.4≥ 1.7 = Polar covalent bond

  1.7≤ EN= ionic bond