Warm Up

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Warm Upwhat do you remember?

• Why do bonds form?
• What is the difference between ionic and covalent
  bonds?

2
Warm Upwhat do you remember?

• Why do bonds form?

3

• What is the difference between ionic and covalent
  bonds?

4
Draw the Lewis Structures and show the behavior
of the electrons.

• Sodium and Bromine

• Fluorine and oxygen
• (you will need 2 F)

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Covalent Compounds

• Nonmetal bonding with another nonmetal
• Electronegativity difference less than 1.67
• Electrons being shared

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Formation of Covalent Bond
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Bond Stability
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Properties of Covalent Compounds

• low melting point
• low boiling point
• many are gas and liquid at room temp
• typically do not conduct electricity when
  dissolved in water
• This is due to the fact that forces of attraction
  between molecules are much weaker when the
  electrons are being shared.

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Ionic vs covalent

• Visual Concepts

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Warm Up- Write the correct formulas from the
names.

• Copper (III) iodide
• Sodium oxide
• Calcium nitride
• Chromium (II) oxide
• Iron (III) sulfide
• When do we need to use Roman Numerals in the name
  of an ionic compound?

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Discuss Signs
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Draw the MO diagram for Carbon and Oxygen
What do the electrons do?? Do we need to worry
about covalent compounds being neutral?
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Are the electrons being shared equally??
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Polar or Nonpolar?

• Nonpolar- electrons are shared equally.
• Polar- electrons are not shared equally.

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Octet Rule

• Noble gases have filled valence shells
• 2 (He) or 8 e-
• Octet Rule tells us that chemical compounds tend
  to form so that atoms obtain an octet of e- in
  its highest energy level.
• Visual Concepts

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Lewis Structure Rules

1. Add up total number of valence e-
2. Pick central atom and create the bonds
3. Surround the adjacent atoms.
4. Put extra electrons on the central atom.
5. Beg, borrow or steal so that all the atoms are
   stable (have a complete octet).
6. Make sure the number of valence e- you started
   with are the number you used!

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Lets do

• CH4
• SiF4
• NCl3

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Draw the Lewis Structures for the following
molecules

• CH3F
• SiCl4
• How many shared electrons?
• How many unshared electrons?
• Are the electrons shared equally?

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Dipoles

• Indicate polarity- dipole points to the most
  electronegative atom!
• Show the unequal distribution of charge

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Exceptions

• Boron trifluoride BF3
• PF5 and SF6 can expand the shell and share more
  electrons. (10 and 12 respectively)

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Diatomic Molecules

• You must memorize these!!
• H2 N2 O2 F2 Cl2 Br2 I2
  (At2)
• Magnificent 7
• I wont hold you responsible for astatine, just
  know that trends in a group apply!

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Naming Covalent Compounds

• Covalent compounds are molecules or molecular
  compounds
• Indicate the number of each atom using
  prefixes..
• change the end of the name to ide

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Covalent Prefixes

• Use the prefixes!
• 1- mono 6- hexa
• 2- di 7- hepta
• 3- tri 8- octa
• 4- tetra 9- nona
• 5- penta 10- deca
• Examples NO
• SiCl4

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Practice

• Formulas to names

1. SO3
2. ICl3
3. PBr5
4. CO
5. CO2

• Names to formulas

• 1. Carbon tetrachloride
• 2. Dinitrogen monoxide
• 3. Dinitrogen tetroxide
• 4. Phosphorus triiodide
• 5. Sulfur heptafluoride

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Homework- You can do these!

• H2Se
• CH2Cl2
• Silicon Tetrachloride
• HCl
• Fluorine
• CH4
• NH3
• Silicon Tetrachloride
• Chlorine

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Warm Up- Thursday

• Write the names from the formulas
• 1. BaSO4
• 2. MnO4
• 3. SiO2
• 4. PO
• 5. NiPO4

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Questions on Homework?

• Lewis Structure WS
• Naming Covalent Compounds WS

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Forming Multiple Bonds

• CO2
• N2O

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Multiple Covalent Bonds

• Bond length and strength
• Triple bonds are the shortest (pm) and have the
  most Energy (kJ/mol)
• Single bonds are the longest (pm) and have the
  least amount of Energy (kJ/mol)

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Sigma s and Pi p bonds

• Sigma (s) bonds are single bonds
• Pi (p) bonds are the bonds that follow in a
  multiple bond situation

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Now you try

• CO
• Oxygen

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Warm Up- Use Dimensional Analysis

• If the ionic radius of F is 133 picometers, what
  is the length in m and nm.
• (106 pm1m)
• The density of water is 2.7 g/cm3. If an
  aluminum can has a mass of 10.4 g, what is its
  volume?

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Polyatomic ions

• Draw the Lewis Structures for the following
  polyatomic ions.
• Phosphate
• Hydroxide
• LS of ions are indicated using and charge

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Polyatomic ions

• Examples

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Warm Up Draw the Lewis Structures and indicate
the dipoles

• CH2F2
• 2. F2
• 3. NO31-
• Indicate the number of shared and unshared pairs
  on each molecule.
• .

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Resonance Structures

• Some molecules cannot be correctly identified by
  a single Lewis structure
• When you can draw two mirror images, you probably
  have a resonance structure
• For example Ozone O3
• Visual Concepts

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Draw the Resonance Structures for

• Selenium Trisulfide

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Questions on the LS WS??

• How did you do on the polyatomic ions??

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Acids to memorize

• Hydrochloric- HCl
• Acetic Acid- HC2H3O2
• Nitric Acid- HNO3
• Sulfuric Acid- H2SO4
• Carbonic Acid- H2CO3
• Phosphoric Acid- H3PO4

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Building Covalent Molecules Activity

1. Fold paper so that you have 6 squares on each
   page.
2. Write the compound formulas in each box as
   indicated on the board.

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Just a few things from last semester

• Your feedback is very important to me!
• a. Students like- CB, notes, activities
• b. Mixed reactions- POGILS, Projects and
  homework amount.
• c. Students didnt like- IB cut and paste,
  worksheet assignment/collection.
• Performance Assessment / Final.
• Writing in science.
• Whats new in the room?

42
Building Covalent Molecules Activity

1. Draw the Lewis Structure for each molecule.
2. Build the molecule using the kits.
3. Determine the Electronegativity of each atom and
   determine bond polarity- draw the dipoles on LS.
4. Draw the 3-D molecule.
5. Determine the molar mass of each molecule.

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Warm Up-

• Write the names from the formulas
• 1. BaSO4
• 2. MnO4
• 3. SiO2
• 4. PO
• 5. NiPO4
• Be sure you are reviewing your Ionic Bonding all
  is fair game for the test next week.

44
Review Questions?

• Test

45
Warm Up

• Determine the formula
• Calcium hydroxide
• Vanadium (IV) oxide
• Phosphorus tribromide
• Chlorine
• Zinc sulfide

• Determine the name
• SrO
• FePO4
• PO3
• HC2H3O2
• O2

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How did you do?

• Determine the formula
• Ca(OH)2
• VO2
• PBr3
• Cl2
• ZnS

• Determine the name
• Strontium oxide
• Iron(III) phosphate
• Phosphorus trioxide
• Acetic acid
• Oxygen

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Just a few things from last semester

• Your feedback is very important to me!
• a. Students like- CB, notes, activities
• b. Mixed reactions- POGILS, Projects and
  homework amount.
• c. Students didnt like- IB cut and paste,
  worksheet assignment/collection.
• Performance Assessment / Final.
• Writing in science.
• Whats new in the room?

48
Molecular Geometry

• VSEPR
• Valence Shell, Electron
• Pair Repulsion
• Theory

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VSEPR

• How a molecule looks in real space (3D).
• Shape is based upon electron domains (where
  electrons are).
• Bonds (doubles/triples count as one domain)
• Unshared electron pairs- actually take more
  space.

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You need to remember

• Electron domains repel each other.
• Unshared pairs repel more than bonding pairs.
• Domains orient themselves as far away from each
  other as possible.

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VSEPR

• Lets use balloons to figure out the molecular
  geometry of various compounds!

52

• Here are some video clips that will
• show it to you again!
• Development of bond angles
• Visual Concepts
• Lone pair geometry
• Visual Concepts

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Guess the shape!
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Polarity- Physical Property

• Look at the entire molecule-
• If there is an unequal distribution of charge
  (dipoles or a bunch of electrons in one spot).
• POLAR
• If all the bonds are nonpolar or the molecule is
  symmetrical (even if it has dipoles), it is
• NONPOLAR

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Lets Discuss These!
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Lets revisit the molecules you built Tuesday

• Shape and Bond Angles?
• Determine the overall polarity.
• You can keep these activities to study be sure
  to bring them to hand in on test day!

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Is Polarity a Physical or Chemical Property?

• Polarity is important in determining the
  reactivity of various molecules.
• It helps us understand the interaction between
  molecules (intermolecular forces).
• It also determines the solubility of the molecule.

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Warm Up Tues. Honors

• Draw the LS and predict the molecular geometry
  and bond angles for the following molecules.
• SO22- SiCI4 BCl3

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Hybridization

• When atoms come together in a covalent bond, they
  overlap orbitals of differing energy creating
  orbitals of equal energy.

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Intramolecular Forces

• We have spent a month talking about
  intramolecular forces the forces between atoms.
  
• What are they called?

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Intermolecular Forces

• Forces of Attraction between Molecules

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These forces affect the physical properties of
compounds

• Melting and Boiling Points
• Volatility
• Solubility

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What does Volatility mean?

• Volatile Liquid Demo
• Lets try to figure out why the alcohol this guy
  uses is more volatile than water.
• Ethanol- C2H6O Draw the LS

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Different types of Intermolecular Forces

• Dipole-Dipole Force- The negative region of one
  molecule is attracted to the positive region of a
  different molecule.
• HCl, NH3
• Induced dipole - When a polar molecule causes a
  nonpolar molecule to become polar (temporary).

• Visual Concepts

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Different types of Intermolecular Forces

• London dispersion - result from the constant
  motion of electrons and the creation of
  instantaneous dipoles.

• LD Video

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Super Important!

• Hydrogen Bonding- When a hydrogen atom (bonded
  to a highly electronegative atom) attracts an
  unshared pair of electrons from the atom of a
  nearby EN atom.

• Video 1- Basic
• Video 2- A little more deep!
• What elements with Hydrogen form H bonds?

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Hydrogen Bonding
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Get into your small groups and discuss why
ethanol is more volatile than water.
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Metallic Bonding

• This is an extremely strong bond
• Delocalized electrons
• Gives metal luster, malleability, ductility,
  conduct electricity and heat

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Look at the Polarity of the Molecule

• Polar Molecule
• One end negative, one end positive
• Dipole
• Molecule that has two poles
• Is created by equal but opposite charges that are
  separated by a short distance

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Memorize!

• Shapes and angles
• Linear 180o
• Trigonal planar 120o
• Tetrahedral 109.5o
• Trigonal pyramidal 107.5
• Bent 104.5
• Trigonal bipyramidal 90o 120o
• Octahedral 90o

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Metals

• Share a sea of electrons
• Explains why so many of them are good conductors
  of electricity.

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Alloys

• Combination of metals
• Bronze copper and tin
• Brass zinc and copper
• Coin metal copper and nickel
• Solder lead and tin

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Substitutional Alloy

• Some of the main metal atoms are replaced by
  other metal atoms of similar size.
• An example is brass where one-third of the atoms
  of the host copper are replaced with zinc atoms.

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Interstitial Alloy

• Formed when some of the holes in the closest
  packed metal structure are occupied by small
  atoms.
• Steel is an interstitial alloy, containing carbon
  atoms in the holes of an iron crystal.

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• Stainless steel is a mixture of Iron, Chromium
  and Carbon.
• What kind of Alloy would it be?

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Questions on the Review???

• I will post review answers on-line feel free to
  come see me to answer questions.
• Be sure to look over your ionic bonding WS.

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Naming Game (Time Permitting)