A. Electronegativity The ability of an atom to attract electrons to itself in a bond

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Types of Bonds

• A. Electronegativity - The ability of an atom to
  attract electrons to itself in a bond
• 1. Periodic Trends (link to size)
• Metals Low Electronegativity
• Non- Metals High Electroneg
• The smaller the atom, the higher the
  electronegativity

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Types of Bonds

• 2. Two ways for atoms to connect
• Molecular Compounds (non-metals) Sharing of
  electrons through covalent or polar covalent
  bonds
• H2 drawing
• b. Ionic Compounds (metal non-metal)
• Exchange of electrons
• NaCl drawing

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Types of Bonds

• 3. Types of bonds
• Electronegatvity Difference
• Example Na-F

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Types of Bonds

• Are the following bonds ionic, polar covalent or
  covalent?
• Ba Br C N
• Be F B H
• O H Be Cl
• P H C H
• O O

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Ionic?

• Ionic Electron is completely removed from one
  atom and goes to another
• a. Metal Low e-neg (loses e-)
• b. Non-metal high e-neg (gains e-)

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Why Do Ionics Steal

• 1. Large difference in electronegativity
• 2. To gain an Octet
• Draw Lewis Dot Pictures for
• NaCl
• CaCl2
• KBr
• MgF2
• AlCl3

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Common Charges
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Common Charges

• What compound forms between
• Na and I
• Ba and Br
• Al and S
• Rb and O

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• What is the formula for the compound
• K and I
• Sr and F
• Al and S
• Sr and N
• Ba and O
• Draw Lewis Dot Structures for the compounds above

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Ionic Solids

• NOT SEPARATE MOLECULES!!!
• Immense group of ions clumped together.
• Electrostatic charge Opposite charges that hold
  ionic crystals together

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Ionic Solids

• 4. Crystal Lattice Regular 3D pattern in an
  ionic solid

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Ionic Solids
at lattice points
ions at lattice points
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Ions in Water

• Water (molecule) dissolves salt (ionic crystal)

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Ions in Water
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Oxidation Numbers

• Involves taking compounds apart
• Oxidation numbers Pretend charges for all
  compounds (if they existed as ions)
• Rules

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Fe H2 P4 Cl2
Elements 0
Monoatomic Ions Charge
Na O2- Al3
Use bankables to calculate the rest
H2S Cl2O Na2SO4 Fe2O3 PO43-
NO3- CaCr2O7 SnBr4
Gr I Gr II
O-2
H
F-
the higher the oxidation , the more oxidized
the element
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Oxidation Numbers
4. Examples HBr FeF2 HNO3 SO4-2
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Oxidation Numbers
5. You try SO32- HCO3- H3PO4 C2H6 XeF4
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Other Salts

• Many ionic compounds are called salts
• CaCl2 Calcium Chloride (Quik-Joe)
• NaHCO3 Sodium bicarbonate(Baking soda)
• NaF Sodium Fluoride (toothpaste)
• CaCO3 Calcium Carbonate(Chalk, antacid)
• NaOH Sodium Hydroxide (Drano)
• MgSO4 Magnesium Sulfate(Epsom Salts)
• All big clumps (crystals) of Ions

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What is a Molecule?

• Group of atoms held together by covalent and
  polar covalent bonds (SHARING)
• Usually composed of non-metals
• Stronger than Ionic bonds
• Separate (discrete) groups of atoms (Ex draw
  several H2O molecules)

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Old School Lewis Dots

• A. Single Bonds (LD and Stick)
• CH4
• Cl2O
• (bonded versus lone pairs)

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The Lone Pear(Pair) rides again!
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Old School Lewis Dots

• You try
• N and H
• H and Cl
• P and F
• Si and H
• NH2CH3

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Old School Lewis Dots

• You try
• Si and I
• CH3CH2OH
• NH2CH2SiCl3

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Old School Lewis Dots

• B. Multiple Bonds (LD and Stick)
• CO2
• C2H2

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Old School Lewis Dots

• You Try
• HCN
• N2
• AlN
• O2

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Lewis Dots

• Rules
• 1. Sum all valence electrons, including charges
• 2. Single Bonds
• 3. Outer atoms get an octet except H
• 4. Center gets rest even if it violates the octet
• 5. Double/triple bonds if center atom still does
  not have an octet

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Lewis Dots

• NH3
• NCl3
• SF6
• Br2O
• ClF5

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Lewis Dots

• You try
• SF4
• H2SO4
• KrF4
• Cl2O
• NH2CH3

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Lewis Dots

• CO2
• HCN
• CN-
• ICl4-
• BrO3-
• NO

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Lewis Dots

• You try
• C2H4
• CO32-
• H3O
• NH4
• PO43-

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Resonance Structures

• Warm-Up O3
• Definition When a molecule can exist in more
  than one arrangement of electrons
• 1. Atoms remain static
• 2. Only the electrons move
• 3. Also called delocalized bonding

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Resonance Structures

• SPECIAL NOTE
• Oxygen doesnt make three bonds for resonance
  structures. DO NOT DRAW MORE THAN TWO BONDS FOR
  AN OXYGEN!! (those structures are not common)

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• PO3-
• HSO3

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Resonance Structures

• Examples
• 1. NO2-, CO32-, CHO2-, HNO3
• 2. Which needs resonance, SO3 or
• SO32-

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Less Than an Octet

• Hydrogen only makes one bond
• More generally, Gr I, II and III
• Especially if with a halogen
• BeCl2 BF3 AlF3

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More Than an Octet

• Non-Metals starting with P
• Have d-orbitals available (3d is first d-orbital)

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PCl5
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Uses of Lewis Dots

• Organic Chemistry
• Proteins
• Acid/Bases
• NH3 - has lone pair for bonding

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Shapes of Molecules

• Valence Shell Electron Pair Repulsion Theory
  (VSEPR)
• Two types of Groups (NH3)
• a. Bonded electrons
• b. Lone Pairs
• VSEPR Valence electron pairs push as far apart
  as possible.

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Shapes of Molecules

• 1. Linear (180o)
• BeH2 CO2

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Shapes of Molecules
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Shapes of Molecules

• 2. Trigonal Planar (120o)
• NO3-

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Shapes of Molecules
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Shapes of Molecules

• 3. Tetrahedral (109.5o)
• CH4

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Shapes of Molecules
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Shapes of Molecules

• 4. Trigonal Pyramidal (107o)
• NH3

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Shapes of Molecules
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Shapes of Molecules

• 5. Angular (104.5o)
• H2O

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Shapes of Molecules
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Shapes of Molecules
O
H
H
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Shapes of Molecules
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Shapes of Molecules

• 6. Trigonal Bipyramid (120o, 90o)
• PCl5

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Shapes of Molecules
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Shapes of Molecules

• 7. Octahedral (90o)
• SF6

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Shapes of Molecules
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• DRAW LEWIS DOT STRUCTURES AND PREDICT THE BOND
  ANGLES FOR
• PH3 GeO2
• PCl5 NCl3
• H2S SiH4
• CF4 SO32-
• SeCl6 SO3

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Shapes of Molecules

• Ex All single bonds
• PH3 H2S SiH4
• SeCl6 AsF5 BeCl2
• CH3F HF BF3

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Shapes of Molecules

• Ex Multiple Bonds
• N2
• HCN
• CO2
• H2CO

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Shapes of Molecules
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Shapes and Formula?

• 1. Examples
• BeH2
• H2O
• BH3
• NH3
• 2. There is no relationship between formula and
  shape

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• Lewis Dot of Ionics
• NaF
• CaCl2
• GaF3

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Electron Density

• 1. Show the tracks of the electrons
• 2. Examples
• H2 H2O
• 3. You try
• CH4 BH2Cl (B is the center)

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Electron Density

• H2 H2O
• CH4 BH2Cl

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Polar Molecules

• 1. Polar molecule Overall, the electrons are
  attracted more to one end of an entire molecule
• 2. Non-Polar Molecule The electrons are spread
  out evenly over the entire molecule
• 3. d-/ d Partial (not full) charges

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Polar Molecules

• BeCl2
• NH3
• CO2

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Polar Molecules

• You Try
• CCl4
• CH3Cl
• CH2Cl2
• CHCl3
• HBeCl
• HBr

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Polar Molecules

• CH3Cl CH2Cl2
• CHCl3 HBeCl HBr

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Polar Molecules

• Hydrogen Bonding
• a. Water Beading
• b. SurfaceTension
• c. Ice
• d. DNA
• e. Miscibility (NH3, ethanol)
• f. Immiscibility (Water and Oil)

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Water Beading
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Surface Tension

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Surface Tension

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Ice

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Surface Tension

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Ice

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DNA

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DNA

DNA is TWO molecules that are hydrogen bonded
(like a zipper)
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DNA

Human Genome Project
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• DNA in one cell 1 meter
• DNA in all your cells 93,000,000 miles

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Miscibility

• Like dissolves like.
• Polar dissolves Polar
• Water, ammonia

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Miscibility

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Miscibility

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Miscibility

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Miscibility

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Miscibility

• Water, alcohol

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Miscibility

• Water, alcohol

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Miscibility

• Water, alcohol

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Miscibility

• Water, alcohol

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Miscibility

• Non-Polar dissolves Non-Polar
• oil paint, thinner

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Miscibility

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Naming Molecules

• Prefixes
• Mono Hexa
• Di Hepta
• Tri Octa
• Tetra Nona
• Penta Deca
• May skip mono for first element

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Naming Molecules

• P4O10
• N2O4
• SiCl2
• Cl2O
• CO

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Naming Molecules

• CO2
• Cl2O7
• SF6
• chlorine dioxide
• diphosphorus tetroxide
• carbon tetrachloride

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• Ban dihydrogen monoxide!!!!!!
• Its a major component of acid rain
• Contributes to soil erosion
• Accelerates the rusting of many metals
• Has been found in tumors
• Even after washing, produce remains contaminated
  by this chemical
• Gets into your house through the pipes

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Naming Molecules

• Household Molecules
• H2O
• HCl
• NH3
• H2SO4

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Polar Molecules

• You Try
• CCl4 NO3-
• CH3Cl H2CO
• CH2Cl2 H2S

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• KrCl4 Si2H4
• BN CH3SiH2PH2
• SiS2 H2SO4
• O
• H O S O H
• O

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The Key to the Universe
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• Al3, Mg2, Na, F-, O2-, N3-
• a) 8 b) -3 c) -6 d) 3
• e) 3 f) 1