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Chemical Bonding Objectives:  Understand why compounds exist in nature.  Indentify and compare the two classes of compounds by their chemical and physical.

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Presentation on theme: "Chemical Bonding Objectives:  Understand why compounds exist in nature.  Indentify and compare the two classes of compounds by their chemical and physical."— Presentation transcript:

1 Chemical Bonding Objectives:  Understand why compounds exist in nature.  Indentify and compare the two classes of compounds by their chemical and physical properties.  Identify and predict compound names and formulas by element’s location on the periodic table.  Illustrate chemical bonding between elements.

2 Periodic Trends: Review Use graph to recall atomic radius trend across a period and down a group on the Periodic Table. Size of an atom influences an atom’s ionization and Electronegativity values.

3 Periodic Trends: Review Ionization Energy:increase Atomic Radius: decreases *Electronegativity: increase *Electronegativity: decreaseIonization Energy: decreaseAtomic Radius: increases

4 Electronegativity Review Electronegativity: The degree of attraction atoms in a compound have toward the bonded electrons. Notice most noble gases do NOT have an electronegativty value because they do not need to participate in chemical bonding-already stable.

5 Chemical Bonding Review Chemical Bonding Review 1.Classify each compound below as ionic or covalent. a.KCl (Ionic: metal and non-metal) b.CO (Covalent: 2 non-metals) c. H 2 O (Covalent:2 non-metals) d. MgCl 2 (Ionic: metal and non-metal)

6 Metals vs. Non-metals Metals vs. Non-metals

7 Chemical Bonding Chemical Bonding Ionic Bonding:  Between a metal and a non-metal atom.  Electronegativity difference between atoms is large.  Transfer of valence electrons.  Ionic Bond = Intramolecular Forces Covalent Bonding:  Between two non-metals.  Electronegativity difference between atoms is small  Share valence electron(s)  Covalent Bond = Intramolecular Forces  Covalent compounds are also called molecules.

8 Ionic Bonding Ionic Bonding  Transfer of valence electrons from a metal atom to a non-metal atom.  Creates a metal ion (cation) and non-metal ion (anion) that are held together by electrostatic attractive forces (chemical bond)  Chemical bonds are intramolecular forces.  Formation of Ionic Compounds

9 Ionic Bonding Ionic Bonding

10 Intramolecular Forces  The chemical bonds within a single compound.

11 Lewis Dot Structures Lewis Dot Structures Lewis Dot Structures: Illustrates valence electronsIllustrates valence electrons for an atom. for an atom. Place electrons (dots) around the elements symbol using cardinal direction. cardinal direction. Do NOT pair electrons Do NOT pair electrons up until you have to. Element# of valence electrons Lewis Dot Structure Na 1 Mg 2 Si 4 S 6 He 2

12 Lewis Dot Structures Lewis Dot Structures

13 Ionic Bonding (Lewis Dot Transfer) Ionic Bonding (Lewis Dot Transfer) Metal (Lewis Dot) Non- metal (Lewis Dot) Ionic Bonding (Lewis Dot Transfer) Ionic Cmpd Chemical Formula Chemical Name (name of the ions)

14 Chemical Bonding Chemical Bonding 1. Classify each compound below as ionic or covalent. a.CO 2 b. AlCl 3 c. Mg 3 P 2 d. H 2 e. H 2 O C I I C C C I I C C 2.a. Which compounds above were formed from the transfer of ve-? All ionic compounds b. Which compounds above were formed from the sharing of ve-? All covalent compounds b. Which compounds above were formed from the sharing of ve-? All covalent compounds 3. For those compounds that share ve-, identify which compounds have polar bonds and which have non- polar bonds. Covalent compounds that do NOT share bonded electrons equally. (CO 2 and H 2 0)

15 Covalent Bonds Covalent Bonds Prentice Hall KY Teacher Express, 2008 Polar Bonds: Where atoms do NOT share bonded electrons equally. Usually 2 different elements making up the bond. Ex. N-----O Non-Polar Bonds: Where atoms share bonded electrons equally. Same elements. Ex. O-----O

16 Ionic Compounds   The overall charge on any ionic compound is always zero.   The ratio of metal to non-metal ions has to equal zero

17 Ionic Compound Nomenclature Ionic Compound Nomenclature How do scientist name ionic compounds?  Binary Ionic Compounds: Simplest compounds, composed of two ions (cation and the anion)  Name the cation and the anion. *Use flow-chart to help you name each ion in the compound.

18 Ions Ions Oxidation number: The charge on an atom.  Some elements have a fixed oxidation number. Primarily representative elements (tall groups on periodic table)  Some elements have multiple oxidation numbers. Primarily transitional elements (short, middle groups on the periodic table).

19 Naming Cations: Metals Naming Cations: Metals  Fixed Oxidation Number ( fixed charge) - Simply the name of the metal -Ex. Al 3+ : aluminum ion  Multiple Oxidation Numbers (multiple charges) -Name of metal and roman numeral to identify what charge is being used. -Fe 2+: iron (II) ion Fe 3+: iron (III) ion

20 Oxidation Numbers and Periodic Table

21 Naming Anions: Non-metals  Non-metals only have a single oxidation # (charge) when becoming an anion.  It is the root word of the non-metal with an –ide ending. Ex. Br 1- = Bromide Ex. P 3- = phosphide

22 Naming Ionic Compounds * Use flow chart to name ionic compounds* Naming Ionic Compounds * Use flow chart to name ionic compounds* 1.KF : potassium fluoride 2.Ca 3 P 2 : calcium phosphide 3.CuBr 2 : copper (II) bromide 4. FeN : iron (III) nitride

23 Naming Ionic Compounds  BaCl 2 : barium chloride  Mn 3 P 2 : manganese (II) phosphide  Ag 2 O: silver oxide  CaBr 2 : calcium bromide

24 Chemical Formula of Ionic Compounds 1. 1.Write the symbol and charge for the cation and the anion If charges balance, then the ions are one to one in the formula If charges do not balance, then use the criss-cross method to establish the correct ratio of ions (subscripts) so they do balance out in the formula.

25 Determine the Chemical Formula Determine the Chemical Formula 1. Aluminum Phosphide: Al 2 P 3 2. Magnesium Chloride: MgCl 2 3. Iron (III) Sulfide: Fe 2 S 3 4. Chromium (II) Oxide: CrO 5. Nickel (II) Bromide: NiBr 2

26 Types of Ions Types of Ions  Monatomic Ions : 1 element makes-up 1 element makes-up the ion.  Polyatomic Ions: 2 or more elements make-up an ion.

27 Mono or Poly Ions? Mono or Poly Ions? a.Na 1+ : mono b. (S0 4 ) 2- : poly c. Cl 1- : mono d.(PO 3 ) 3- : poly

28 Ionic Compounds a. Li (OH): lithium hydroxide b. Fe 2 (CO 3 ) 3 : iron (III) carbonate  Sodium Sulfate: Na 2 (SO 4 ) d. Chromium (II) Phosphate : Cr 3 (PO 4 ) 2

29 Covalent Compounds Covalent Compounds  Covalent compounds = molecules  When naming covalent compounds prefixes are primarily used. *Use flow chart* Prefixes:  Mon(o)=1 atom Hexa = 6 atoms  Di= 2 atoms Hepta= 7 atoms  Tri= 3 atoms Octa= 8 atoms  Tetra= 4 atoms Nona= 9 atoms  Penta= 5 atoms Deca= 10 atoms

30 Covalent Compounds Covalent Compounds 1.Chemical name of covalent compounds a.CO 2 = carbon dioxide b.P 2 O 5 = diphosphorus pentoxide c.O 2 = oxygen 2. Chemical formula of covalent compounds. a.dihydrogen monosulfide = H 2 S b.dinitrogen trioxide= N 2 O 3 c.bromine= Br 2

31 Chemical Compounds Chemical Compounds  I can name, predict, and critique chemical compounds.  I can identify, interpret, and investigate properties of chemical compounds.

32 Chemical Compounds Venn Diagram Ionic Compounds Covalent Compounds

33 Chemical Compounds Objectives: Use your chemical compound venn diagram to establish a hypothesis for your physical properties lab.

34 Physical Properties Lab Physical Properties Lab  Electrical Conduction Lab: Which samples do you think will conduct electricity?  Crystal Structures Lab: Which of the samples do think will grow crystals the fastest? the slowest?

35 Physical Properties Lab Physical Properties Lab  Electrical Conduction Lab: Which samples do you think will conduct electricity?  Crystal Structures Lab: Which of the samples do think will grow crystals the fastest? the slowest?

36 Electrical Conduction Lab Data Electrical Conduction Lab Data Grp # Tap H 2 O Deionized dH 2 O Salt soln. (NaCl) Sugar Soln. C 6 H 12 O 22 Vinegar Soln. C 2 H 4 O 2 Baking Soda Soln. NaHCO 3 Borax Na 3 BO Yes (Y) if substance conducted electricity, No (N) if did not.

37 Tap Water Tap Water Ground water produced the passageways at Mammoth Cave. In so doing, water picks up many contaminants. One common contaminant is limestone residue. Why tap water conducte electricity.

38 Properties of Chemical Compounds Properties of Chemical Compounds  Which kind of compounds conduct electricity best?

39 Properties of Ionic Compounds Properties of Ionic Compounds Ionic compounds can conduct an electric current when melted or dissolved in water. 7.2

40 Properties of Chemical Compounds Properties of Chemical Compounds Why can’t chemical compounds in the solid state conduct electricity? 7.2

41 Properties of Chemical Compounds Properties of Chemical Compounds  The orderly arrangement of atoms/ions produces beautiful crystalline structure.  Which compound from the lab produced crystals faster/slower?  7.2

42 Salt Crystal Lattice Salt Crystal Lattice  Na+ and Cl- ions produce a solid, repeating 3-D structure called a crystal lattice. 7.2

43 Sugar Crystal Lattice Sugar Crystal Lattice  Sugar molecules will produce a crystal lattice, but it will occur slower.  Weaker attractive forces (partial charges) between molecules. production/th_med_crystals.jpg content/uploads/2008/12/sugar-molecule- 02.jpg o o o o CC C C

44 Covalent Bonds Covalent Bonds Prentice Hall KY Teacher Express, 2008 Polar Bonds: valence electrons shared unequally between atoms in a molecule. Non-Polar Bonds: valence electrons shared equally between atoms in a molecule.

45 Electronegativity Values Electronegativity Values

46 Properties of Ionic Compounds Properties of Ionic Compounds Chemical CompoundsMelting Point ( o C)Boiling Point ( o C) Cr 2 O 3 2,2664,000 SrF 2 1,4702,489 CCl CH 4 O Chemical Compounds Article From the table below, what can be concluded about the differences in melting and boiling points of chemical compounds? Ionic compounds have higher melting and boiling points.

47 Properties of Chemical Compounds Collection of Ionic Compounds Collection of Covalent Compounds Why do ionic compounds in general have higher melting and boiling points? stronger attractive forces between ions

48 Properties of Chemical Compounds Properties of Chemical Compounds  Ionic Compounds are primarily solids at room temperature. Ex. salt  Molecules can be a solid, liquid, or gas at room temp. Examples:. O 2 and CH 4 (C 8 H 18 ) (C 8 H 8 )

49 Properties of Chemical Compounds Collection of Ionic Compounds Collection of Covalent Compounds Which type of compound do you think is more brittle when stress is applied to it?

50 Properties of Ionic Compounds Properties of Ionic Compounds  Ionic crystals are brittle when stress is applied.  Repulsion increases when similar ions are force together

51 Properties of Molecules  Molecules are more resilient (durable) than ionic compounds.  Why?

52 Chemistry Chemistry  Drawing molecular structures and identify polar bonds.

53 Chemical Structure of Covalent Compounds   Non-metals atoms share valence electrons to reach stability. (Octet Rule)   Types of covalent bonds between two atoms: a. a.Single Bond (share 2ve-) b. b.Double Bond (share 4 ve-) c. c.Triple Bond (share 6 ve-)

54 Drawing Molecular Structures 1. 1.Draw Lewis Dot Structures for each element in the molecule Calculate the total number of valence electrons in the molecule Share unpaired valence electrons between atoms. Each bond represents a pair of shared electrons. Ask: How many unpaired electrons can each atom share with one another? Determines the # of bonds between atoms. 4. Add lone pairs to atoms in the molecule if needed. 5. Check to make sure each atom is stable in your molecular structure (Octet Rule) and all valence electrons are accounted for. Octet Rule Exception: Hydrogen

55 Molecules: Lewis Dot Sharing Molecules: Lewis Dot Sharing Molecular Formula Lewis Dot SharingMolecular Structure Polar Bonds

56 ChemicalCompoundsReview Ionic Compounds:  Transfer of valence electrons.  Usually a metal and a non-metal ion. Covalent Compounds:  Sharing valence electrons.  Consists only of non-metals.

57 Ionic vs. Covalent Compounds

58 Covalent Compounds  Illustrate and model covalent bonding with Lewis Dot and Molecular structures.  Illustrate and predict which molecules are polar.  Identify and predict the types of intermolecular forces between molecules in the liquid and solid state.

59 Molecular Geometry  Shape of the molecule in 3-D space.  VSEPR Theory : -(Valence Shell Electron Pair Repulsion) -How bonds and lone pairs are arranged around the central atom in a molecule to minimize electron repulsion.

60 Molecular Geometry Molecular Geometry  Using the VESPR hand-out and the molecular model kit, classify each of these molecules. Molecules Molecular Structure Molecular Geometry Name; Bond Angle Polar or Non-polar Molecule NCl 3 CBr 4 SCl 2 SiO 2 PF 5

61 Electronegativity Values Electronegativity Values

62 VSEPR Theory VSEPR Theory (Valence Shell Electron Pair Repulsion) liakatas.org

63 Polar Molecules Polar Molecules  Polar molecules: One end of the molecule is partially positive and the other end is partially negative.  Also called dipole molecules.  False: All molecules that have polar bonds are classified as polar molecules.

64 Molecules and Polarity Molecules and Polarity ieshermanosbilingual.blogspot.com en.wikipedia.org 3dchem.com P F F F.. O H H

65 Polar vs. NonPolar Molecules Polar vs. NonPolar Molecules Molecules Molecular Structure Molecular Geometry Name; Bond Angle Polar or Non-polar Molecule NCl 3 trigonal pyramidal (109.5) CBr 4 Tetrahedral (109.5) SCl 2 Bent (109.5) SiO 2 Linear (180) PF 5 Trigonal bypyramidal (some 120; some 90)

66 Polarity of Molecules Polarity of Molecules What is the point of classifying molecules as polar or non-polar?  Predict the degree of solubility for a molecule. Solubility: Like dissolves like.  Predict the type of intermolecular forces holding molecules together in the solid and liquid states. 

67 Intermolecular Forces Intermolecular Forces itl.chem.ufl.edu

68 Types of Intermolecular Forces Types of Intermolecular Forces 1.Dipole Forces : Attraction b/w polar moleculesAttraction b/w polar molecules Partial charges oppositelyPartial charges oppositely attract attract Prentice Hall: Chemistry

69 Types of Intermolecular Forces Hydrogen Bonds : Very strong dipole force.Very strong dipole force. Pre-resquiste for H bonding to occur: H must be covalently bonded to a very electronegative element (N, O, F).H must be covalently bonded to a very electronegative element (N, O, F). Prentice Hall: Chemistry

70 Types of Intermolecular Forces 3. London Dispersion Forces:3. London Dispersion Forces: Caused by random motion of electrons in each bonded atom.Caused by random motion of electrons in each bonded atom. Temporary dipole forces.Temporary dipole forces. Occur in non-polar and polar molecules.Occur in non-polar and polar molecules. elmhurst.edu I I

71 Chemistry Chemistry a.What is the chemical name of your molecule? b. Draw its molecular structure (use your rules) c.Identify if the bonds are polar or non-polar bonds. Explain your answer. d.Does your molecule have single, double or triple bonds? Explain your answer.

72 Bell Ringer: Molecules Bell Ringer: Molecules 1.a. Draw the molecular structure of NBr 3 b. Identify its geometrical shape? b. Identify its geometrical shape? c. Is it a polar or non-polar molecule? c. Is it a polar or non-polar molecule? d. Would it be soluble in water? Explain. d. Would it be soluble in water? Explain. e. What type of intermolecular force(s) would e. What type of intermolecular force(s) would exist between NB 3 molecules in the solid or liquid state? exist between NB 3 molecules in the solid or liquid state?

73 Metallic Bonding Metallic Bonding What are some properties of Metallic Bonding?

74 Metallic Bonding Metallic Bonding


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