1. Chemical Bonding and Interactions
Unit 7: Physical Science

2. Bellringer Day 01 Define: Valence electrons.
How can you find the number of valence electrons in an element?

3. Types of Bonds

4. Chemical Bonds
Recall that each element on the periodic table has its own properties, and numbers of particles.
Chemical bonds form when two elements combine to form compounds
This process results when atoms lose, gain, or share electrons in order to make their outer shells “full”
Remember, atoms with a full outer shell tend to be most stable

5. Types of Bonds
There are three types of chemical bonds you should know:
Ionic
Covalent
Metallic

6. Ionic Bonds Ionic bonds form between a metal and a nonmetal
In this type of bond, atoms transfer electrons, creating charges (remember, charged atoms are called ions)
Ionic Bonds

7. In this example, lithium has 1 valence electron, while fluorine has 7.
Lithium will give away its extra electron to fluorine. Now they both have full outer shells.
Ionic Bond Example
Lithium has lost an electron. It now has a positive charge. It is a cation.
Fluorine has gained an electron. It now has a negative charge. It is an anion.

8. Covalent Bond Covalent bonds form between two nonmetals
In covalent bonds, neutral atoms share electrons
Covalent Bond

9. In this example, carbon has 4 valence electrons, and oxygen has 6.
By sharing their valence electrons, all shells are filled with 8 electrons, making them stable.
Covalent Bond Example

10. Metallic Bond Metallic bonds form between two metals
In metallic bonds, valence electrons are pooled and shared
Metallic Bond

11. What type of bond would form between…?
Hydrogen and oxygen?

12. What type of bond would form between…?
Lithium and Fluorine?

13. What type of bond would form between…?
Carbon and Hydrogen?

14. Bellringer Day 02
What is the difference in how covalent bonds and ionic bonds form?
What is the name of a positive ion? Negative?

15. Naming Chemical Formulas

16. Ionic Compounds
Recall that Ionic compounds are formed when metals react or bond with nonmetals (ionic bond)
Remember, a cation is a positively charged ion, and an anion is a negatively charged ion

17. A. Oxidation Number 1+ 2+ 3+ 4+ 3- 2- 1- The charge on an ion.
Indicates the # of e- gained/lost to become stable. 1+ 2+ 3+ 4+ 3- 2- 1-

18. Naming Ionic Compounds
We can use a set of rules to name ionic compounds when they form!
Naming Ionic Compounds

19. Rules of Ionic Names Write the names of both elements, cation first.
Change the anion’s ending to -ide.
For ions with variable oxidation #’s, write the oxidation # in parentheses using Roman numerals. Overall charge = 0.
Write the names of polyatomic ions.

20. Ionic Names Example: Sodium and Bromine (NaBr)
First: Write the names of both elements, cation first.
Sodium will lose an electron and become positive. It is our cation. Bromine will gain one and become negative. It is an anion.
So, we would begin by writing sodium bromine
Second: Change the anion’s ending to -ide
Our name is sodium bromide

21. Ionic Names Example: Transition
If it is a transition metal, you will likely need a Roman numeral. A good rule of thumb is usually the number of anions you have in the molecule is equal to the charge of the cation, and vice versa.
Example: TiBr3
Tin is a transition metal, so it will need a roman numeral
It will pick up the subscript 3 from Bromine and become Tin(III) Bromide
If it is not a transition metal, don’t worry about the roman numerals!

22. Ionic Names: Polyatomic Ions
Sometimes, names will be dictated by a chart
Na2CO3-sodium carbonate
Notice CO3 on the chart
to the right

23. Ionic Formulas
Now you see how to name them using the formulas; next, let’s look at how to get the formulas from the names!

24. Ionic Formulas Write each ion. Put the cation first.
Overall charge must equal zero.
If charges cancel, just write the symbols.
If not, crisscross the charges to find subscripts.
Use parentheses when more than one polyatomic ion is needed.
Roman numerals indicate the oxidation #.

25. Examples: Ionic Formulas
potassium chloride
magnesium nitrate
copper(II) chloride
K+ Cl-  KCl
Mg2+ NO3-  Mg(NO3)2
Cu2+ Cl-  CuCl2

26. C. Ionic Formulas calcium oxide aluminum chlorate Ca2+ O2-  CaO
iron(III) oxide
Ca2+ O2-  CaO
Al3+ ClO3-  Al(ClO3)3
Fe3+ O2-  Fe2O3

27. Bellringer Day 03 Name the following compound: Cu3P
Write the formula for the following compound: cobalt (III) oxide

28. Molecular Compounds
Recall that covalent bonds are formed between two nonmetals
Atoms are linked together by sharing electrons

29. Naming Molecular Compounds
Write the names of both elements.
Change the final ending to -ide.
Add prefixes to indicate subscripts.
Only use mono- prefix with oxide.

30. Molecular Names mono- SUBSCRIPT PREFIX 1 2 3 4 5 6 7 8 di- tri- tetra-
penta-
hexa-
hepta-
octa-
SUBSCRIPT 1 2 3 4 5 6 7 8

31. Molecular Names CCl4 N2O carbon tetrachloride SF6 dinitrogen monoxide
sulfur hexafluoride

32. Writing Molecular Formulas
Write the more metallic element first.
Add subscripts according to prefixes.

33. Molecular Formulas phosphorus trichloride dinitrogen pentoxide PCl3
dihydrogen monoxide
PCl3
N2O5
H2O

34. B. Molecular Formulas The Seven Diatomic Elements
Br2 I2 N2 Cl2 H2 O2 F2

35. Bellringer Day 04 Write the name of the following compound: N2O4
Write the formula for the following compound: diphosphorous pentoxide

36. Balancing Equations

37. Review: Chemical Bonds
Ionic Bonds
Between a metal and nonmetal
Atoms transfer electrons
Charged atoms
Covalent Bonds
Between two nonmetals
Atoms share electrons
Neutral atoms

38. Chemical Reactions (Rxn)- change (Δ) of one or more substances into new substances!

39. Chemical Reactions Reactants are substances that combine or change
Products are the new substances that are produced
Chemical Reactions

40. Conservation of Mass Mass is never created or destroyed
This means that the mass of the products equals the mass of the reactants!
Conservation of Mass

41. Writing Equations
A chemical equation uses formulas and symbols to describe a chemical reaction and the products it produces
Coefficients-numbers which represent the number of units of each substance in a reaction
Subscripts- number which represents the number of atoms in a molecule of a particular element

42. Writing Equations

43. Balanced Equations
Chemical equations must be balanced because of the law of conservation of energy!
Energy can’t be created or destroyed-the elements in the equation don’t disappear, they’re still there in a different form
The numbers, therefore, should match on each side

44. Balancing Chemical Equations
Make a chart
List elements
Count Elements
Balance (add/mult.)
Things you cannot do:
Change a subscript
Place coefficient in middle-must go in beginning

45. Example

46. Practice
H2 + O2 = H2O

47. Practice
HgO  Hg + O2

48. Practice
NiCl2 + NaOH  Ni (OH)2 + NaCl

49. Practice
C3H8 + O2  CO2 + H2O

50. Practice
Al + Fe3N2  AlN + Fe

51. Practice: You Try!
Na + Cl2  NaCl

52. Balance the chemical equations below:
Bellringer Day 05

53. Bellringer Day 06
Balance the chemical equations below:

54. Types of Chemical Reactions

55. Exothermic Vs. Endothermic
Exothermic Reaction-releasing energy in the form of heat
Ex. Forming a chemical bond (releases energy)
Endothermic Reaction-absorbing energy in the form of heat
Ex. Breaking a chemical bond (requires energy)

56. Types of Chemical Reactions
Single Replacement
Double Replacement
Decomposition
Synthesis
Combustion (slide needs to include combustions of hydrocarbons and them not fitting in with other 4 types)

57. Synthesis Synthesis means to put things together to make it whole
A synthesis reaction is when two or more simple compounds combine to form a more complicated one.
General formula: A + B  AB
Example: 2H2+O22H2O

58. Decomposition Decomposition means to separate or break down
A decomposition reaction is when a complex molecule breaks down to make simpler ones
General formula: AB  A + B
Example: H2SO4 H2O + SO3

59. Single Replacement
Single displacement: This is when one element trades places with another element in a compound.
General Formula: A + BC  B + AC
Example: Mg + H2O  MgO + H2

60. Double Replacement
Double displacement: This is when the anions and cations of two different molecules switch places, forming two entirely different compounds.
General Formula: AB + CD  AD + BC
Example: HCl + NaOH  NaCl + H2O

61. Combustion
A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat.
General Formula: CxHx + O2  CO2 +H2O
Example: CH4 + 2O2  CO2 + 2H2O

62. Bellringer Day 07
What is the difference between a synthesis reaction and a decomposition reaction?
Define: endothermic and exothermic.

63. Acids and Bases

64. What are Acids and Bases?
The Arrhenius Theory:
Classifies a substance as an Acid if it produces hydrogen ions H(+) in water
Classifies a substance as a Base if it produces hydroxide ions OH(-) in water

65. Common Acids Notice all formulas begin with H
Hydrochloric (muriatic) acid, HCl (strong)
Sulfuric acid, H2SO4 (strong)
Acetic acid, HC2H3O2
Nitric acid, HNO3 (strong)
Citric acid , H3C6H5O7
Strong acids are those which completely disassociate their atoms when mixed with water

66. Common Bases Notice all formulas end with OH Sodium Bicarbonate
Hydroxides
Sodium Hydroxide, NaOH
Potassium Hydroxide, KOH
Calcium Hydroxide, CaOH
Magnesium Hydroxide, Mg(OH)2
Barium Hydroxide, Ba(OH)2 (strong base)
Ammonium Hydroxide, NH4OH (weak base)
Strong bases are those which completely disassociate in water

67. The pH Scale
The pH scale measures how acidic or basic a substance is (ranges from 0-14)
A substance that is neither acidic or basic is neutral. A pH of 7 is neutral
Scale reading less than 7 indicates an acid
Scale reading greater than 7 indicates a base

68. The pH Scale

70. Common Characteristics of Acids and Bases
pH < 7
Reacts with a metal to form hydrogen gas; carbonates
Strong acids are very conductive
Turns blue litmus indicator red
pH > 7
React with fats/oils
Strong bases are very conductive
Turn red litmus paper blue

71. Household Uses of Acids and Bases
Carbonated drinks
Vinegar
Lemon Juice
Shampoo
Toothpaste…
Baking soda
Oven cleaner
Drain cleaner
Soap…

72. Neutralization Reactions
Reaction in which acids and bases react to form salts and water
Neutralization Reactions

73. Bellringer Day 08 How can you tell if something is an acid or a base?
What are some common household uses of acids and bases?

74. Bellringer Day 09
Compare and contrast the differences between properties of acids and bases.

75. Test Review

76. Day 10: Test Day
Take a few minutes to study!