Notes One Unit Ten chapter SixChemical 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-1shared unequally.• One atom attracts the electrons more.

Ionic Bonding

Ionic Bonding • Ionic compound-metal and nonmetal.

• Ionic compounds dissolve in polar solvents.

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

Electronegativity

Electronegativity

Calculating Bond TypeElectronegativity Difference … E < 0.5: covalent. 0.5 < E < 2.0: polar covalent. E > 2.0: ionic.

3.0-2.1=0.9PC

2.1 -2.1=0C

3.5 -1.2=2.3Ionic

Bond Polarity and Dipole Moments

•

Polarity and Dipole Moments Demo

[He]2sLi 1

[He]2sBe 2

[He]2s 2PB 2 1

[Ne]3sNa 1

[Ne]3s 3PS 2 4

[Ar] 4s 3dAs 2 104p3

[Xe]6s 4fOs 2 145d6

Element Electron Configuration Electron Dot Diagram

Li

Be

B

Na

S

As

Os

X X

X

X X X X X X

X

Stable Electron Configuration

Na2O

NaO Na

O [He] 2s 2P2 6

Na [Ne]3s0

8e-18e-1

Na+1

Na+1

-1-2

Make Molecular Lewis Dot Formulas

HHH2

H2 is stable like helium. He

Make Molecular Lewis Dot Formulas

N

N2

N

8e-1 8e-1

Make Molecular Lewis Dot Formulas

S F

F

SF2

8e-1

8e-1

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) ModelValence Shell Electron Pair Repulsion(VSEPR) Model Predicting Molecular ShapesPredicting Molecular Shapes Summary of VSEPR Molecular Shapes Resonance

Valence Shell Electron Pair Repulsion(VSEPR) ModelValence 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

HH

H

B F

F

Lewis structure for BF3

F+1+2+3 -1

-1

-1

Domains?3

0NB VS B

3e-1 Geometry?

Trigonal Planar

Molecular Geometry?Trigonal Planar

Predicting Molecular ShapesPredicting Molecular Shapes

NO

O

O

Predicting Molecular ShapesPredicting Molecular Shapes

Domains?Lewis structure for NO

3-1

3

0NB VS B

3e-1 Geometry?

Trigonal Planar

Molecular Geometry?Trigonal Planar

-1

P F

FF

F

F

Predicting Molecular ShapesPredicting Molecular Shapes

Domains?Lewis structure for PF

5

5

0NB VS B

5e-1 Geometry?

Triangular Bipyramidal

Molecular Geometry?Triangular Bipyramidal

Predicting Molecular ShapesPredicting Molecular Shapes

Domains?Lewis structure for H

2O

4

2NB VS B

2e-1 Geometry?

Octahedral

Molecular Geometry?Bent

O H

H

O

HH

O

S F

FF

FF F

Predicting Molecular ShapesPredicting Molecular Shapes

Domains?Lewis structure for SF

6

6

0NB VS B

6e-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

FNa + Na+ + F[ ]_

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• N2O4

• dinitrogen tetroxide*

• CO

• carbon monoxide*

• CO2

• carbon dioxide

• SO2

• sulfur dioxide

• P2O5

• 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