1. Chemical Bonds
Chapter 6

2. SmartStarter
What is the octet rule?

3. SmartStarter
Draw the electron dot diagram for ionic compound MgCl2

4. Compare – Eyes on Chemistry
Epsom Salts
Rock Salt
Sucrose
One more…
WHAT DO YOU NOTICE ABOUT THEIR STRUCTURE?

5. NaCl

6. Valence Electrons and Lewis Dot Structure (AKA Electron Dot Diagram)
Remember: Octet Rule? Valence Electrons?
How many valence electrons in…
Example: Sulfur
Your turn 1-20 – count off!

7. Stable Electron Configurations

8. Stable Electron Configurations

9. Stable Electron Configurations

10. Stable Electron Configurations

11. Stable Electron Configurations

12. Stable Electron Configurations

13. Stable Electron Configurations

14. Stable Electron Configurations

15. Stable Electron Configurations

16. Where we are going from here… Chemical Bonds  Ionic, Covalent, Metallic

17. Relationships are weaker when you
Ionic Bonding
Relationships are weaker when you
take/borrow/steal…
It means someone had to
give/lend/be robbed
…Where the analogy breaks down…
Who is left feeling more negative?
Who is more positive?
What happens when negatives and positive are near each other?

18. Ca+ion vs. Anion

19. Oxidation #
OXIDATION NUMBERS
Oxidation numbers can be positive, negative or zero. An oxidation number of zero is associated with a pure element in its ground state. If the oxidation number of an atom is positive, the atom has fewer electrons than its ground state. If the oxidation number of an atom is negative, the atom has a greater number of electrons than its ground state.
ELECTRONEGATIVITY
Electronegativity describes the tendency of an atom to attract the electrons in a chemical bond. Elements with a large electronegativity exert a greater pull on electrons than elements with small electronegativities. Ultimately, the electronegativity difference between the atoms in a compound can help determine the nature of the compound's bonds. When the electronegativity difference is between zero and 0.4, the bond between atoms is covalent. When the electronegativity difference is 1.8 or more, the bond is ionic. When the electronegativity difference is between 0.5 and 1.7, the bond is polar covalent.
ELECTRONEGATIVITY AND OXIDATION NUMBERS
Because electronegativity dictates the distribution of electrons in a molecule, it can also help you determine oxidation numbers. For example, consider a water molecule. The oxygen atom has an electronegativity of 3.5, whereas each hydrogen atom has an electronegativity of 2.2. Therefore, this molecule is polar, and the oxygen atom attracts the electrons away from the hydrogen atoms. This imbalance is reflected in the oxidation numbers. Oxygen in a water molecule has an oxidation number of -2, whereas each hydrogen atom has an oxidation number of +1. In general, the atom with a larger electronegativity will have a negative oxidation number, and the atom with a smaller electronegativity will have a positive oxidation number.
TRENDS IN ELECTRONEGATIVITY
The electronegativity of elements on the periodic table generally increases as you move horizontally across the table and decreases as you move vertically down the table. The periodicity of electronegativity helps determine trends in oxidation numbers. For example, the elements closer to the right edge of the table tend to have negative oxidation numbers due to their higher electronegativities. Conversely, the elements on the left side of the table tend to have positive oxidation numbers due to their lower electronegativities.
- Can you predict which elements will form ionic bonds with which?
- Which groups with which groups?
- Metals with Metals? Metals with Non-metals?

20. MgCl2 Lattice shape depends on the arrangement of the atoms.
RATIO = 1:2
Crystal Lattice
Lattice shape depends on the arrangement of the atoms.
2 Factors: Size of atoms and ratio of elements

21. Trend is the opposite of the atomic size trend, so the bigger the atom, the easier it is to steal electrons off of it.
Also, the more electronegative the atom is, the more energy it takes to ionize it…Why???? It takes more energy to steal than to be stolen from?

22. IONIC BONDS

23. What are the periodic trends with electronegativity?

25. SMARTStarter: What kind of bond forms between sodium and fluorine?
Electronegativity

26. Covalent Bonding (6.2) Relationships are stronger when you share
Bond Strength: Covalent bond > Ionic bonds
One pair of shared electrons?
Two pairs of shared electrons?
Three pairs of shared electrons ?
Three fish

27. Molecules = ? - Define it! Electron Dot Diagram of Covalent Bonds –
Molecule = neutral group of atoms held together by one or more covalent bonds
Dr. B - Practice

28. Polar Covalent Bond Share…but not equally
Results in partial charges = polarity
EXAMPLE: Water

29. Nonpolar or PURE Covalent Bonds
Formula: CH4
Name: Methane
Name
Carbon dioxide (CO2) has two polar C-O bonds, but the geometry of CO2 is linear so that the two bond dipole moments cancel and there is no net molecular dipole moment; the molecule is non-polar. In methane, the bonds are arranged symmetrically (in a tetrahedral arrangement) so there is no overall dipole.
Formula
Carbon dioxide (CO2)
Shape Matters!
Geometry
Symmetry

30. Molecular Compound – bonded molecules
Forces of attraction that hold molecules together in a liquid or solid
- Stronger in polar or nonpolar molecules?
Stronger in polar molecules…
Ex. Hydrogen bonds
(Van der Waals Forces)

31. POLYATOMIC IONS:
A polyatomic ion, also known as a molecular ion, is a charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. The prefix poly- means "many," in Greek, but even ions of two atoms are commonly referred to as polyatomic
-ite and -ate Some polyatomic anions contain oxygen. When an element forms two oxygen containing anions they are named with different suffixes/endings:
-ite = the one with less oxygen
-ate = the one with more oxygen
Examples:
NO2- Nitrite NO3- Nitrate
SO32- Sulfite SO42- Sulfate

32. Nomenclature -- How do you name or talk about compounds and molecules?
Formulas - describes the ratio of ions in the compound
Name – words to describe/identify it.
Carbon dioxide (CO2)
Name
Formula
Binary compound = exactly two different elements Metal + Nonmetal = ?
Nonmetal + Nonmetal = ?
Metal + Metal = ?
A binary compound is a chemical compound that contains exactly two different elements. Examples of binary ionic compounds include calcium chloride (CaCl2), sodium fluoride (NaF), and magnesium oxide (MgO), whilst examples of binary covalent compounds include water (H2O), and sulfur hexafluoride (SF6)
Metal + Nonmetal = ionic bonds => ionic compound
Nonmetal + Nonmetal = covalent bonds => molecule
Metal + Metal = metallic bonds
Examples:
calcium chloride (CaCl2), sodium fluoride (NaF), and magnesium oxide (MgO)
water (H2O), and sulfur hexafluoride (SF6)

33. Talking Ionically…Formula
When writing an ionic FORMULA between a metal and a nonmetal follow these
5 steps:
Write the symbols for the metal and the nonmetal.
Write the valences as superscripts above each symbol.
Drop the + and - sign.
Crisscross the valences so they become the subscript for the other element.
Reduce subscripts whenever possible. Only when both are divisible by a number greater than one.

34. SmartStarter  Show me how…

35. Show me how…

37. Pattern/Rules for Naming Ionic Compounds: NAME…
name of cation + name of anion + “-ide”
Ionic Compounds - Naming of anions
-ide The -ide ending is added to the name of a monoatomic ion of an element.
H- Hydride F- Fluoride O2- Oxide S2- Sulfide N3- Nitride P3- Phosphide

38. Practice
Using a periodic table & oxidation numbers find the formula and name of these ionic compounds:
magnesium and fluorine
aluminum and sulfur
Nitrogen and calcium*
barium and iodine
bromine and potassium*
aluminum and phosphorus
strontium and oxygen
nitrogen and magnesium*
cesium and phosphorus
Check your answers
sodium and phosphorus = Na3P
magnesium and fluorine = MgF2
aluminum and sulfur = Al2S3
calcium and nitrogen = Ca3N2
barium and iodine = BaI2
potassium and bromine = KBr
aluminum and phosphorus = AlP
strontium and oxygen = SrO
magnesium and nitrogen = Mg3N2
cesium and phosphorus = Cs3P

39. When the metal (ca+ion) is a Transition Metal…
More than one type of ions possible
A Roman numeral in parentheses, following the name of the element, is used for elements that can form more than one positive ion. This is usually seen with metals.
You can use a chart to see the possible valences for the elements.
Fe2+ Iron (II) Fe3+ Iron (III)
Use Roman Numerals to indicate the charge
Ex. Copper (II) ion + Chlorine  Cu2+ + __Cl-  CuCl?
Cu+ Copper (I) Cu2+ Copper (II)
Cu2+ + _2_Cl-  CuCl2
Cu+ Cuprous Cu2+ Cupric
-ous and -ic Although Roman numerals are used to denote the ionic charge of cations, it is still common to see and use the endings -ous or -ic. These endings are added to the Latin name of the element (e.g., stannous/stannic for tin) to represent the ions with lesser or greater charge, respectively. The Roman numeral naming convention has wider appeal because many ions have more than two valences.
Fe2+ Ferrous Fe3+ Ferric

40. Write the names of the possible valences of Chromium
Write the names of the possible valences of Chromium. How would Chromium (III) and Oxygen bond? (Give the name and formula).
Chromium(III) iodide, also known as chromium triiodide, is an inorganic compound with the formula CrI3. It is a black solid that is used to prepare other chromium compounds.[2]
Being isomorphous with chromium(III) chloride (CrCl3), it exhibits a cubic-closest packing arrangement in a double-layer crystal lattice. In this structure, chromium exhibits octahedral coordination geometry.
2 Cr + 3 I2 → 2 CrI3

41. Practice Using a periodic table try these then check your answers.
iron(III) and phosphorus
copper(II) and fluorine
silver(I) and sulfur
manganese(II) and nitrogen
lead(IV) and iodine
copper(II) and bromine
gold(II) and phosphorus
lead(IV) and oxygen
silver(I) and nitrogen
copper(II) chloride
Check your answers
Transition Metal Answers
iton(III) and phosphorus = FeP
copper(II) and fluorine = CuF2
silver(I) and sulfur = Ag2S
manganese(II) and nitrogen = Mn3N2
lead(IV) and iodine = PbI4
copper(II) and bromine = CuBr2
gold(II) and phosphorus = Au3P2
lead(IV) and oxygen = PbO2
silver(I) and nitrogen = Ag3N
copper(II) chloride = CuCl2

42. Compounds containing POLYATOMIC IONS
Polyatomic Ion: covalently bonded group of atoms that has a positive or negative charge and acts as a unit
When you write formulas for compounds containing a polyatomic ion:
Write the symbols for the metal and the polyatomic ion.*
Write the valences as superscripts above each.
Drop the + and - sign.
Crisscross the valences so they become the subscript for the other element.
If you have more than one of the polyatomic ion, you must encase it in parenthesis and place the subscript outside.
You can only reduce a subscript outside the parenthesis of a polyatomic ion - you cannot change the formula the polyatomic ion.
*In the case of ammonium (the only polyatomic cation) you would write it first and then the anion

43. Let me show you…

44. Let me show you…

45. Practice…You show me!
Try these using a periodic table and a list of polyatomic ions.
aluminum and sulfate
ammonium and sulfur
barium and hydroxide
magnesium and phosphate
lead(IV) and sulfite
strontium and carbonate
zinc(II) and phosphate
ammonium and oxygen
calcium and nitrate
tungsten(II) and sulfate
Check Answers
Compounds with Polyatomic Ions Answers
aluminum and sulfate = Al2(SO4)3
ammonium and sulfur = (NH4)2S
barium and hydroxide = Ba(OH)2
magnesium and phosphate = Mg3(PO4)2
lead(IV) and sulfite = Pb(SO3)2
strontium and carbonate = SrCO3
zinc(II) and phosphate = Zn3(PO4)2
ammonium and oxygen = (NH4)2O
calcium and nitrate = Ca(NO3)2
tungsten(II) and sulfate = WSO4

46. Covalent (Molecular) Compounds

47. COVALENT FORMULAS: TWO NONMETALS
Because covalent compounds share electrons they can share in different ways and can form many compounds between the same two elements.
IMPORTANT: You never crisscross valences to determine covalent (two nonmetals) formulas.
So just how do you write the formulas? Prefixes - that's how.
Here are six covalent compounds that form between nitrogen and oxygen:
nitrogen monoxide = NO
nitrogen dioxide = NO2
dinitrogen oxide = N2O
dinitrogen trioxide = N2O5
dinitrogen tetroxide = N2O4
dinitrogen pentoxide = N2O5
We saved the easiest formulas for last.
In ionic compounds you always crisscross valences to determine the formulas. In covalent compounds atoms share electrons so there isn't any valence to crisscross. IMPORTANT: You never crisscross valences to determine covalent (two nonmetals) formulas. So just how do you write the formulas? Prefixes - that's how.
Because covalent compounds share electrons they can share in different ways and can form many compounds between the same two elements. For example, you know two compounds that that exist between carbon and oxygen: CO carbon monoxide and CO2 carbon dioxide. The NAMES of covalent compounds contain prefixes that tell you how many atoms of each element is in the compound. Here are the prefixes used in covalent compounds:

48. NAMES
*Lowest electronegativity goes first or Left to right on the P-Table

49. Practice – GIVE THE FORMULA
Just look at the name and you have the formula for a covalent compound!
Go ahead and try these:
sulfur dioxide
dihydrogen oxide
phosphorus pentafluoride
carbon tetrachloride
aluminum trichloride
Check your answers
Covalent Compounds Answers
sulfur dioxide = SO2
dihydrogen oxide = H2O
phosphorus pentafluoride = PF5
carbon tetrachloride = CCl4
aluminum trichloride = not possible. Never use prefixes in ionic compounds (contain a metal cation). This compound would simply be called aluminum chloride.

50. 6.4 Metallic Bonds From this video you should learn:
How they form….common pool of electrons
Metallic Lattice structure ?
How they give metal its strength…?
Alloys…combined properties

51. Kinesthetic Learning: Bonding Charades
Four Types of Bonds = four possible answers
Ionic Bonds
Pure Covalent Bond
Polar Covalent Bond
Metallic Bonds
Procedure:
Form your group of 6-8
Get your assignment
3 minutes to plan your skit
Perform when called on
GROUP WHO IS IDENTIFIED FASTEST FOR EACH CATEGORY GETS A PRIZE!
RULES:
No noise
No letters/words/numbers/Symbols

52. Metallic Bonds
Bond that keeps metal atoms together is called metallic bond. In metals;
Number of valence electrons is smaller than number of valence orbitals. So, they have many empty valence orbitals.
Their ionization energies are small and they are weakly attracted by nucleus.
Valence electrons of metals can jump to the other atom's valence orbitals. This free movement of electrons makes metals good conductor of electricity and heat. All valence electrons of metals can behave like this.
P-TABLE TRENDS
In periodic table, as we go from top to bottom in metal group, strength of metallic bond and melting point decrease.
In periodic table, as we go from left to rşght in same period, strength of metallic bond and melting point increase.

53. Lab IDEA Chemical Bonding Lab (The name’s Bond, Covalent Bond.)
Chemical bonding lab?! This sounds like fun! Or we could just wash test tubes and tin can lids for the first half hour of class. You know, either one would be fine.
What types of elements make up your compounds? (Be specific and list this by compound.)
Calcium chloride- calcium (metal), chlorine (nonmetal)
Potassium iodide- potassium (metal), iodine (nonmetal)
Sodium chloride- sodium (metal), chlorine (nonmetal)
Citric acid- carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Phenyl salicylate- carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Sucrose- carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Which atoms in your compounds have high ionization energy? Low ionization energy? High electronegativity? Low electronegativity?
Calcium, potassium, and sodium all have relatively low electronegativities and ionization energies, while chlorine, iodine, carbon, hydrogen, and oxygen all have relatively high electronegativities and ionization energies.
There’s a scale for bond type based on electronegative differences here (it’s from Quinnipiac University). Determine the bond type of each compound you used today using the electronegativity values on page 161 in your book.
Calcium chloride- ionic (metal/nonmetal)
Potassium iodide- ionic (metal/nonmetal)
Sodium chloride- ionic (metal/nonmetal)
Citric acid- covalent (nonmetal/nonmetal)
Phenyl salicylate- (nonmetal/nonmetal)
Sucrose- (nonmetal/nonmetal)
Which compounds were ionic? Which covalent?
The calcium chloride, potassium iodide, and sodium chloride are all ionic, while the citric acid, the phenyl salicylate, and the sucrose are all covalent.
What properties are associated with ionic compounds? What properties are associated with covalent compounds?
Ionic compounds have very high melting and boiling points, are soluble in water, and almost always conductive when dissolved in a solution or melted.
Covalent compounds have low melting and boiling points (they melted almost immediately) and did not conduct electricity, although the citric acid did, it was not as bright as the other compounds.
Lab IDEA
Ionic compounds have very high melting and boiling points, are soluble in water, and almost always conductive when dissolved in a solution or melted.
Covalent compounds have low melting and boiling points (they melted almost immediately) and low conductivity.
Sugar dissolves
Salt dissolves

54. MORE Practice/Review
Quia.com

55. POLYATOMIC ION: A covalently boned group of atoms that has a positive or negative charge and acts as a unit … ex. Iron (III) Oxide Fe(OH)3

56. Electronegativity

57. HOW DO THE ELECTRON CONFIGURATIONS CHANGE?
ACROSS THE SAME PERIOD?
DOWN THE SAME GROUP?
1. a. Describing Based on Table 1, how do the electron configurations
of atoms within each period change as you go from lower to
higher atomic number? How do the electron configurations
change as you go across the table from one period to another
within a row?
b. Identifying Identify the number of valence electrons that
characterize each of the four different periods shown in Table 1.
c. Predicting In order to become more stable, predict whether
atoms of elements in periods 1A and 2A in Table 1 would gain or
lose electrons. Make a similar prediction about the atoms of
elements in periods 6A and 7A in Table 1.

58. HOW DOES THE RADIUS OF AN ATOM CHANGE WHEN IT BECOMES AN ION?
How does the radius change…
When it becomes a cation?
When it becomes an anion?
Radius of the atom
Charge of the ion (# electrons lost/gained)
Radius of an ion of the atom
2. a. Comparing and Contrasting Check your predictions from
question 1c by looking at Table 2 and finding the number of
valence electrons gained or lost by atoms when they become
ions. Compare periods 1A and 2A with periods 6A and 7A. For
example, how many electrons are gained or lost by lithium (Li)?
By oxygen (O)?
b. Drawing Conclusions In general, how does an atom’s radius
change when it becomes a cation? An anion?
c. Predicting The last element in Period 1A is francium (Fr). It is
not shown in either table. Predict how many valence electrons
francium has, whether it gains or loses electrons to become an
ion, and how its radius changes when it becomes an ion.
Predict the radius change and # of valence electrons for Francium (Fr)

59. Not learned in this class….but interesting:
hypo- and per- In the case where there is a series of four oxyanions, the hypo- and per- prefixes are used in conjunction with the -ite and -ate suffixes. The hypo- and per- prefixes indicate less oxygen and more oxygen, respectively.
ClO- Hypochlorite ClO2- Chlorite ClO3- Chlorate ClO4- Perchlorate
bi- and di- hydrogen Polyatomic anions sometimes gain one or more H+ ions to form anions of a lower charge. These ions are named by adding the word hydrogen or dihydrogen in front of the name of the anion. It is still common to see and use the older naming convention in which the prefix bi-is used to indicate the addition of a single hydrogen ion.HCO3- Hydrogen carbonate or bicarbonate HSO4- Hydrogen sulfate or bisulfate H2PO4- Dihydrogen phosphate