Notes One Unit Ten chapter Six Chemical bond Covalent Bonding Polar Covalent Ionic Bonding Electronegativity Lewis Electron Dot Diagrams Lewis Dot Formula Rules

Chemical bond Attractive force-binds atoms. Covalent bond-sharing e -1. Ionic bond-transfer of e -1.

Covalent Bonding A covalent bond results when electrons are shared by nuclei.

Polar Covalent Polar covalent bond-e -1 shared unequally. One atom attracts the electrons more.

Ionic Bonding

Ionic compound-metal and nonmetal. Ionic compounds dissolve in polar solvents.

Electronegativity Bond polarity is due to electronegativity. Electronegativity – attraction for shared e -1.

Electronegativity

Calculating Bond Type Electronegativity Difference … E < 0.5: covalent. 0.5 < E < 2.0: polar covalent. E > 2.0: ionic =0.9 PC 2.1- =0 C =2.3 Ionic

Bond Polarity and Dipole Moments

Polarity and Dipole Moments Demo

[He] 2sLi 1 [He] 2sBe 2 [He] 2s2PB 2 1 [Ne] 3sNa 1 [Ne] 3s3PS 2 4 [Ar] 4s3dAs p 3 [Xe] 6s4fOs d 6 ElementElectron ConfigurationElectron Dot Diagram Li Be B Na S As Os

X X X XXXXXX X

Stable Electron Configuration Na 2 O Na O O [He] 2s2P 26 Na [Ne] 3s 0 8e -1 Na +1 -2

Make Molecular Lewis Dot Formulas H H H2H2 H 2 is stable like helium. He

Make Molecular Lewis Dot Formulas N N2N2 N 8e -1

Make Molecular Lewis Dot Formulas S F F SF 2 8e -1

Lewis Dot Formula Rules 1) Total all valence electrons. [Consider Charge] 2) Select a fine a central atom. Lowest Electronegativity 3) Place a pair of electrons in each bond. 4) Complete octets of surrounding atoms. [H=2 only] 5) Place leftover electrons in pairs on the central atom. 6) If there are not enough electrons to give the central atom an octet. look for multiple bonds by transferring electrons until each atom has eight electrons around it.

Notes Two Unit Ten chapter Six Valence Shell Electron Pair Repulsion(VSEPR) Model Valence Shell Electron Pair Repulsion(VSEPR) Model Predicting Molecular Shapes Predicting Molecular Shapes Summary of VSEPR Molecular Shapes Resonance

Valence Shell Electron Pair Repulsion(VSEPR) Model 1)Draw the Lewis structure. 2)Count the electron pairs (triple and double bonds equal one pair). 3)Determine electron geometry. 4)Determine molecular geometry. N H H H

B F F Lewis structure for BF 3 F Domains? 3 0 NB VS B 3 e -1 Geometry? Trigonal Planar Molecular Geometry? Trigonal Planar Predicting Molecular Shapes

N O O O Domains? Lewis structure for NO NB VS B 3 e -1 Geometry? Trigonal Planar Molecular Geometry? Trigonal Planar

P F F F F F Predicting Molecular Shapes Domains? Lewis structure for PF NB VS B 5 e -1 Geometry? Triangular Bipyramidal Molecular Geometry? Triangular Bipyramidal

Predicting Molecular Shapes Domains? Lewis structure for H 2 O 4 2 NB VS B 2 e -1 Geometry? Octahedral Molecular Geometry? Bent O H H O H H O

S F F F F F F Predicting Molecular Shapes Domains? Lewis structure for SF NB VS B 6 e -1 Geometry? Octahedral Molecular Geometry? Octahedral

Resonance

Stable Electron Configuration How many s and p electrons are need for stability? 8e -1 How many does Na Have in the highest s and p? 1e -1 How many does it need to lose or gain? 1e -1 lose How many does F Have in the highest s and p? 7e -1 How many does it need to lose or gain? 1e -1 gain Look at your electronegativity table

Notes three Unit Ten Chapter Six Naming Nonmetal Compounds Electronegativity Prefix Examples

Naming Nonmetal(?) Compounds The more metallic (Lower Electronegativity) element is written first, except for hydrogen. Which one is written first? Oxygen or Nitrogen Which one is written first? Sulfur or Oxygen Which one is written first? Uranium or Nitrogen Which one is written first? Sulfur or Fluorine How can we quickly tell which one has the lower electronegativity?

Electronegativity

Prefix Identifies the Numbers of each Element The number of each atom type is identified by a Greek prefix: mono di tri tetra penta hexa hepta octa nona deca The prefix mono is dropped for the first element.

Examples N 2 O 4 dinitrogen tetroxide* CO carbon monoxide* CO 2 carbon dioxide SO 2 sulfur dioxide P 2 O 5 diphosphorus pentoxide* *Mono, penta and tetra are changed to mon, pent and tetr when used as the prefix for oxygen.

Summary of VSEPR Molecular Shapes