How many valence electrons do atoms want to obtain? Bell Ringer How many valence electrons do atoms want to obtain?

Chemical Bonding A bond is the electrostatic force of attraction between two particles (atoms, ions or molecules)

They are formed/broken during Chemical Reactions Why/How Bonds Formed? They are formed/broken during Chemical Reactions Formed = release energy Broken = absorb energy

Valence Electrons - want to achieve happiness Why form a bond? Valence Electrons - want to achieve happiness “Octet Rule” - want a full valence shell = HAPPY!

Ionic Covalent Metallic Atoms Involved - metal and nonmetal Types of Bonds Atoms Involved Ionic Covalent Metallic - metal and nonmetal - nonmetal + nonmetal - metal + metal

Naming Compounds                                      Jump Jump

H+1 + O-2  H2O Find the correct formula for a compound!! Kriss-Kross will make you... Find the correct formula for a compound!! Use the oxidation #’s Put the positive one first H+1 + O-2  H2O

+2 -1  CaBr2 Ca + Br +2 -2 +2 -1 Mg + (OH)  Mg(OH)2 Sr + O  Sr2O2 Criss-Cross practice +2 -1  CaBr2 Ca + Br +2 -1 Mg + (OH)  Mg(OH)2 +2 -2  Sr2O2  SrO Sr + O

+1 -2  Na2Se Na + Se +3 -3 +3 -1  Fe(HCO3)3 Al + PO4  Al(PO4) Criss-Cross practice +1 -2  Na2Se Na + Se +3 -1  Fe(HCO3)3 Fe (III) + (HCO3) +3 -3 Al + PO4  Al(PO4)  Al3(PO4)3

Naming Ionic Compounds Remember: A bond between a metal and a non-metal atom The metal keeps its name, and the non-metal ends in -ide KBr  CaCl2  Potassium Bromide Calcium Chloride

Wings – Bonding Video

What are the formulas for the compounds between: Bell Ringer What are the formulas for the compounds between: Oxygen and Phosphorus Iodine and Barium

Speed Bonding

HON – 17 H2 N2 O2 F2 Cl2 Br2 I2 Diatomic Molecules   Diatomic Molecules 3 HON – 17 As pure elements, these seven elements form molecules containing two atoms H2 N2 O2 F2 Cl2 Br2 I2  

HON – 17 Diatomic Molecules   Diatomic Molecules 3 HON – 17 As pure elements, these seven elements form molecules containing two atoms Transition Elements  

Free atoms have more energy than bonded atoms Bonding Atoms combine to form compounds By bonding atoms together, their properties change I. Bonding H2O O2 H2 A.Chemical Bond This is the attractive force between atoms or ions Results from the rearrangement of valence electrons B. Energy Changes As a chemical bond forms, atoms are brought to a lower energy state  Exothermic Free atoms have more energy than bonded atoms

Making Bonds Exothermic Breaking Bonds Endothermic Bonding Free atoms Potential Energy H H Energy Energy H H Bonded atoms H2 H2 Making Bonds Exothermic Breaking Bonds Endothermic Chemical Energy Energy released as a bond is formed Energy used to break chemical bonds Chemical energy is considered potential (stored) energy.

energy energy Strong Bond C. Stability Two atoms drop to lower energy states when they bond. They are now more stable More energy released during bond formation, more stable the bond More energy released during bond formation Stronger Bond Need more energy to break these bonds apart energy energy Releases lots of energy energy Releases little energy. energy To break it, add lots of energy To break it, add little energy Weak Bond Strong Bond

Bonding Bonds between Atoms As we said before, atoms can bond together by moving their valence electrons around Actually, atoms can either lose, gain or share electrons. This gives us several types of bonds e- e- e- e- e- Bonds between Atoms - + Ionic Bond Atoms transfer electrons Creates ions Forming ions An ion is formed when atoms lose or gain electrons Ion = Charged atom due to a loss or gain of electrons

Naming Ionic Compounds Binary Ionic Compounds - change the end of the non-metal to -ide MgI2  Magnesium Iodide K2O  Potassium Oxide CoBr2  Cobalt (II) Bromide CoBr3  Cobalt (III) Bromide

Naming Ionic Compounds When you have more than two elements, refer to Ref. Table E. NaOH  Sodium Hydroxide (NH4)(NO2) Ammonium Nitrite KMnO4  Potassium Permanganate Ni2(CrO4)3  Nickel (II) chromate

Bell Ringer What would the oxidation number be for Iron in the following compounds: Fe2O3 FeS

What bond type? You must look at the types of atoms and their electronegativity differences. Ionic - bond between a metal and a non-metal Electronegativity difference should be = to or > than 2.0 This means that one atom can pull an e- from another atom Big Dog vs Little Dog Results in the formation of ions Mn + F  1.6 - 4.0 = 2.4 K + O  0.8 - 3.4 = 2.6

= What bond type? Higher ionic character Metal + nonmetal Ionic bond Further apart on the Periodic table Greater difference in electronegativity = Higher ionic character Higher ionic character High ionic character

Writing Formulas Lab

What are the formulas for the following compounds: Sodium thiocyanate Bell Ringer What are the formulas for the following compounds: Sodium thiocyanate Ammonium oxide

Compound Naming Race

Writing Formulas Lab

What type of bonds are in the following compounds? Bell Ringer What type of bonds are in the following compounds? Calcium Bromide Sulfur Oxide

What bond type? You must look at the types of atoms and their electronegativity differences. Covalent - bond between two non-metals Electronegativity difference should be less than 2.0 This means that one atom is not able to pull an e- away Two of the same sized dogs DOES NOT FORM IONS!!! C + Cl  2.6 - 3.2 = 0.6  2.7 - 2.7 = 0.0 I + I

What bond type? Covalent - bond between two non-metals Specific Types Polar Covalent - the unequal sharing of e- Electronegativity differences of 0.5 – 1.9 - Fe2O3  1.8 3.4 = 1.6 Results in partial charges on the atom Non-Polar Covalent - the equal sharing of e- Electronegativity differences of 0.0 – 0.4 Usually only in diatomic molecules O2  3.4 - 3.4 = 0.0

What bond type? Nonmetal + nonmetal Covalent bond Small difference in electronegativity Ternary substance - compound containing polyatomic ion Polyatomic ion is covalently bonded together Bond between polyatomic ion and atom is ionic MgSO4 Results in a compound having both IONIC and COVALENT bonds covalent Ionic

= sea of electrons What bond type? Alloy - Metal + Metal Metallic bond Electrons are free to move all over, not bound to one nucleus Alloy - Different metal atoms mixed together Brass – copper and zinc Bronze – copper and tin Gold – Gold, silver, copper

Lewis Structures of Ions and Ionic Compounds Ionic compounds can also be drawn as Lewis structures. Positive ion  Cation Since all the valence electrons are removed, no valence electrons are shown. + The charge is written above Na Negative ion  Anion The added valence electrons indicate a full valence shell. - Cl Brackets are added and the charge is written on the outside

Ionic compounds Write the positive ion next to the negative ion, and include their charges Cl - Na +

H2O H H O O H H Covalent compounds First write element symbols and then draw their valance electrons. H2O H H O Now move the atoms to pair up any unpaired electrons O H H

Electron Dots in Compounds: Give the formula and dot diagram for the compound formed from the following compound: CO2 EN difference ?

Fluorine and Magnesium Electron Dots in Compounds: Give the formula and dot diagram for the compound formed from the following elements: Fluorine and Magnesium EN difference ?

Electron Dots in Compounds: Give the formula and dot diagram for the compound formed from the following elements: Strontium and Bromine EN difference ?

Electron Dots in Compounds: Give the formula and dot diagram for the compound formed from the following elements: NH3 EN difference ?

Sodium hydroxide Electron Dots in Compounds: Give the dot diagram for the compound: Sodium hydroxide

Phosphorus and Chlorine Bell Ringer Give the formula and dot diagram for the compound formed from the following elements. Phosphorus and Chlorine δ+ δ- Cl Cl Cl P Cl Cl Cl

Inter-state vs Intra-state

What are they? Hydrogen Bonding The attractive force between the hydrogen attached to a highly electronegative atom of one molecule and a highly electronegative atom (N, O, F only) of a different molecule. Only found in polar covalent compounds Individually a very weak bond

Unique properties of water Hydrogen Bonding Unique properties of water Very High M.P. and B.P. Less dense as a solid High Heat of Vaporization Sweating, climate moderation High Surface Tension Fewer molecules to be attracted to therefore a stronger attraction

Hydrogen bonding is the strongest of the intermolecular bonds Hydrogen bonding is the strongest of the intermolecular bonds!!!! (click for video)

Bubble Lab

Strontium and Iodine Sr I I Bell Ringer Give the formula and dot diagram for the compound formed from the following elements: Strontium and Iodine -1 +2 Sr I I

BUBBLES Hydrogen Bonding The Jesus lizard – the Basilisk lizard scroll down to view movie

Naming Covalent Compounds Rules are similar to ionic compounds, just need to add prefixes for the number of atoms mono- 1 2 3 4 5 6 7 8 9 10 hexa- di- hepta- tri- octa- tetra- nona- penta- deca-

Naming Covalent Compounds Try the following: CO2 CCl4 Carbon dioxide Carbon tetrachloride Dinitrogen monoxide Diphosphorus pentoxide N2O P2O5

Naming Covalent Molecules wkst 1

Physical Properties of CF4 and NH3 at STP Bell Ringer Physical Properties of CF4 and NH3 at STP Compound MP (ºC) BP (ºC) Solubility in water @ 20ºC CF4 -183.6 -127.8 Insoluble NH3 -77.7 -33.3 Soluble State evidence that indicates that NH3 has stronger intermolecular forces of attraction than CF4. Draw the lewis dot diagram for CF4. Is it a polar or non-polar molecule

Molecular Polarity Molecules - are only covalently bonded Polarity of molecules - - completely dependent on the shape of the molecule - molecules are only polar if they have polar covalent bonds - if you can draw one straight line and all the (+) are on one side and all the (-) are on the other side, the molecule is polar Dipole Molecule which has a + side and a - side A molecule is either polar or non-polar with respect to charge

Molecular Polarity Assigning + and - to atoms The atom with the higher electronegativity gets the - The atom with the lower electronegativity gets the + Asymmetrical charge distribution Negative(-) end and Positive(+) end - results in the formation of a Polar molecule Symmetrical charge distribution Equal distribution of charge - results in the formation of a Nonpolar molecule Examples - N + - - + - H--Cl H H H O == C== O + + + nonpolar polar polar

Molecular Polarity wkst

Explain, in terms of electrons, why the bonding in NaCl is ionic? Bell Ringer Explain, in terms of electrons, why the bonding in NaCl is ionic?

Name that Bond!

Like Dissolves Like Polar Molecules - Non-polar molecules - Dissolve in polar solvents Non-polar molecules - Dissolve in non-polar solvents Ionic substances - Dissolve in polar solvents

Some terms to know... Dissociation - Electrolyte - The process where ionic compounds split (separate) into their respective ions Electrolyte - A substance containing free ions that makes the substance electrically conductive

Bell Ringer Draw the Dot Diagrams for the following compounds and determine if they are polar or non-polar, and name them: H2O CH4

You might have to share with another group to get 4. Molecular Models Lab Connectors # Needed Spheres Sticks 6 Black 2 Red Springs 4 Yellow You might have to share with another group to get 4. Green 1 Blue

III. VSEPR Class Shape Model Example AX Linear HCl AX2 CO2 AX3 Trigonal Planar BH3 AX4 Tetrahedral CH4 : AX3 Pyramidal NH3 .. :AX2 BENT H2O

What are the names of the following compounds: CoI3 MgSO4 Bell Ringer What are the names of the following compounds: CoI3 MgSO4

When does something conduct electricity? A substance will conduct electricity IF it has freely moving charged particles Particles can be ions, electrons, etc. as long as they can move Metal Conducts electricity in solid or liquid form Freely moving electrons allows the electricity to flow. Ionic substance Does NOT conduct in solid form Ions are locked in place Has charges, but not free moving Liquid When melted, can conduct electricity Ions are mobile enough to move past each other + - - - + + - + - - + +

When does something conduct electricity? Solution In solution, ions separate Dissociate Ions are free to move, conducts electricity Covalent Solid Doesn’t conduct electricity No charged particles Liquid Doesn’t conduct electricity No charged particles Some types of covalent molecules can be broken down to make ions Solution Ionization Conducts some electricity, because only a few of the molecules in the sample are broken down

Forces Between Molecules (IMF)’s Used to determine a substances properties – only found in covalently bonded substances Relatively weak compared to ionic, metallic, and even covalent bonds Examples Dispersion forces – for your college education Dipole-Dipole forces – again something for college Hydrogen bonding – we’ve done these Molecule-ion attractions – we’ll look at these

Intermolecular Forces Molecule-Ion Attractions – the attraction between the ions and molecules of water in a solution A Good Animation

AKA – Molecular Substances Bonds: Review Ionic Covalent Hard Good Conductors Not as solids High MP & BP Dissolve in Polar Substances - water AKA – Molecular Substances Generally soft Poor Conductors No charged particles Low MP & BP

+ + H H H O H O H H + + H H H N H N H Specific Covalents Coordinate Covalent Bond - one atom donates BOTH electrons that are shared + + H Hydronium ion H H O H O H H + + H H H N H Ammonium ion N H

Intermolecular Forces 2. Dispersion Forces – weak IMF between non-polar molecules - formation of temporary polarity Bigger molecule = Stronger force He, Ne Ar or Kr

Dissolving Video Molecular Forces We know how atoms are held together as molecules How are molecules held together when they are liquid and solids? Dipole Interaction + - O -- H Polar bond Has a + side and a - side + - Look at the whole H2O molecule  H O H Dissolving Video + We can divide this molecule into a + side and a - side This is called a POLAR molecule Or a DIPOLE

Molecular Polarity handout

Lab Check in

Bonding Packet

Some Common Geometries See also polarity Note Sheet Linear Trigonal Planar Tetrahedral See also polarity Note Sheet

Structure Determination by VSEPR Water, H2O The electron pair geometry is TETRAHEDRAL 2 bond pairs 2 lone pairs The molecular geometry is BENT.

Intermolecular Forces Affect on Boiling Points Stronger force = Higher Boiling Point

Bell Ringer Give the name of a substance that can NOT conduct electricity in the solid phase but can as a liquid. Explain why.

Name the following compounds: Bell Ringer Name the following compounds: PCl3 K2C2O4

Conductivity Lab

Covalent Compounds Covalent bonds are classified as single, double, or triple bonds depending on the number of electrons shared between the two nuclei.

Intermolecular Forces Intermolecular forces are attractive forces between molecules. Intramolecular forces hold atoms together in a molecule. Intermolecular vs Intramolecular 41 kJ to vaporize 1 mole of water (inter) 930 kJ to break all O-H bonds in 1 mole of water (intra) “Measure” of intermolecular force boiling point melting point DHvap DHfus DHsub Generally, intermolecular forces are much weaker than intramolecular forces. 11.2

What are the names of the following compounds: KCH3COO BaCr2O7 Bell Ringer What are the names of the following compounds: KCH3COO BaCr2O7

11.2

Types of Intermolecular Forces 3. Dipole-Dipole Forces Attractive forces between polar molecules Orientation of Polar Molecules in a Solid 11.2

Covalent Bonds

FLORIDA STATE

Draw the electron dot diagram for the following : Bell Ringer Draw the electron dot diagram for the following : Magnesium Iodide ion

1. Barium Sulfite 2. SrS 3. Cesium Selenide 4. KClO3 Quiz 1. Barium Sulfite 2. SrS 3. Cesium Selenide 4. KClO3 5. Calcium Sulfide

6. BaCrO4 7. Strontium Fluoride 8. NaNO3 9. Cs(ClO2) Quiz 6. BaCrO4 7. Strontium Fluoride 8. NaNO3 9. Cs(ClO2) 10. Magnesium Oxalate

What types of chemical bonds exist? Bell Ringer What types of chemical bonds exist?

1. Barium Sulfate 2. CaO 3. Potassium Oxide 4. Na2CO3 Quiz 1. Barium Sulfate 2. CaO 3. Potassium Oxide 4. Na2CO3 5. Magnesium Oxide

6. SrCrO4 7. Barium Chloride 8. NaNO3 9. MgSO4 10. Beryllium Sulfite Quiz 6. SrCrO4 7. Barium Chloride 8. NaNO3 9. MgSO4 10. Beryllium Sulfite

Are you positive you lost the cat? Sodium Atom Chlorine Atom +11 -11 -10 +17 -17 -18 +1 Total charge Total charge -1 a negative ion Atom is considered a positive ion neutral Atom is considered neutral Called an Anion Called a Cation In an ionic bond, one electron from sodium is transferred to chlorine Cation Positive ion due to the loss of electrons meow. Anion Negative ion due to the gain of electrons Are you positive you lost the cat?

Examples - Determine the type of ion shown and explain how it was made from a neutral atom. Ion Type of Ion How it was made K+ Ca+2 O-2 Br- cation Lost 1 electron cation Lost 2 electrons anion Gained 2 electrons anion Gained 1 electron

Draw the electron dot formula for neutral atoms of Na and F + - Na F All atoms want a full octet in their valence shell. This is a stable configuration. When ionic bonding occurs,the one valence electron in Na is transferred to F 1 + 8 Notice how both atoms have a full octet? 2 Na F has gained an electron to get a total of 8. Na uses its full shell underneath as a full valence The attraction between the + and - ion causes the bond Review Ionic bonds 1. Electrons are transferred 2. Ions are created Cation lost e-, anion gained e- 3. Very strong bond. Has high melting and boiling points, and a very rigid structure 4. Creates ionic substances

Hydrogen and helium do not need 8 electrons, only 2 Covalent Bonds a. Electrons in bonds - No transfer of electrons - Electrons are shared between valence shell of atoms - Weaker bonds than ionic In covalent bonding, atoms get a full octet by sharing electrons between their valence shells Special Case Hydrogen and helium do not need 8 electrons, only 2 So the molecule H2 looks like H H H H

Covalent Bonds The octet rule The shared electron pair In covalent bonding, atoms still want to achieve a noble gas configuration The octet rule But rather than losing or gaining electrons, atoms now share an electron pair. The shared electron pair is called a bonding pair

Molecules Look at the parts of H2O O H H O H H H---O | H Not H--O--H This indicates that H2O looks like H---O | H Not H--O--H Or H--H--O Review In a covalent bond, electrons are shared between valence shells There is NO transfer of electrons, so no ions are formed Their bonds are weaker, have lower melting and boiling points If atoms are covalently bonded, they make Molecules