1. Atomic Theory and Bonding
Chapter 4.1:
Atomic Theory and Bonding
Vocabulary: matter, mass, volume, substance, chemical change, physical change, state, particle, gas, liquid, solid, attract

2. Vocabulary: matter pure substance atom mixture Atomic theory nucleus
molecule
compound
chemical change
element
property
pure substance
mixture
nucleus
proton
neutron
electron
subatomic particle
orbital shell
valence shell

3. Chemistry is the study of...
MATTER!!!

4. What is matter? Anything with mass and volume
Found in 3 phases: liquid, solid, gas
Cannot be created or destroyed,
it only changes form

5. Atomic Theory
John Dalton came up with the Atomic Theory (1800’s)
Atomic Theory: Everything is made of tiny particles called atoms.

6. Atoms and Molecules: Atoms are the smallest part of an element
Molecules are two or more atoms combined

7. ATOMS FORM COMPOUNDS Atoms join together to form compounds.
A compound is composed of two or more different atoms combined in a specific way.
Ex: Oxygen and hydrogen are atoms/elements; H2O is a compound.

8. ATOMS FORM COMPOUNDS

9. CHEMICAL CHANGE
A chemical change occurs when the arrangement of atoms in compounds changes to form new compounds.

10. CHEMICAL CHANGE
Sodium Na (solid)
Chlorine
Cl (gas)
Salt
NaCl

11. Vocabulary
Definition
Atom
The smallest particle of an element that still has the properties of the element
Element
A pure substance that cannot be broken down into simpler materials.
Contains only one kind of atom
Compound
A pure substance that has more than two types of elements bonded chemically together
ex: H2O, CH4, H2SO4

12. A pure substance made of two or more atoms joined together
Molecule
A pure substance made of two or more atoms joined together
ex: H2O, CH4, H2SO4, H2, N2, Cl2
Property
Something that is used to tell one substance apart from another
ex: colour, density, melting point…
Pure substance
Has identical properties in every sample (elements and compounds)
Mixture
Two or more substances put together but not chemically combined
Can have different properties for different samples

13. The Atom: An atom is the smallest part of an element
The nucleus is the center of the atom
Most of the mass of an atom is in the nucleus
nucleus

14. The Atom: The nucleus is composed of -positive protons
-neutral neutrons
Protons have a positive charge
Neutrons have no charge
(they are neutral)

15. ATOMIC THEORY
Because protons have a + charge, the nucleus always has a + charge.
Protons and neutrons have the same mass

16. ATOMIC THEORY -Electrons have a negative (-) charge
-Electrons are found outside the nucleus, in orbital shells.
-Electrons are MUCH smaller than protons and neutrons
(about of the mass of a proton or a neutron)
-Electrons have a negative (-) charge

17. Subatomic particle: the “parts” of an atom
Protons
Neutrons
Electrons

18. Orbital shell: The space that the electron uses when it travels around the nucleus.
The outside orbital shell is called the valence shell

19. Assignment:
BIG BOOK p

20. Chapter 4.1: The Periodic Table
Vocabulary: matter, mass, volume, substance, chemical change, physical change, state, particle, gas, liquid, solid, attract

21. Vocabulary:
ion
atomic number
atomic mass
common ion charge
metal
non-metal
transition metal
period
family / group
alkali metal
alkaline earth metal
halogen
noble gas

22. Atoms and Ions the number of protons = number of electrons
Atoms are the smallest part of an element
Atoms are NEUTRAL (no charge)
the number of protons = number of electrons

23. Atoms and Ions Ions are an atom with an electrical charge
Ions can have a + or – charge
The number of electrons changes

24. Introduction to the Periodic Table
Common ion charge
Other ion charge
Name
Symbol
Atomic number
Average atomic mass

25. The number of protons determines what element it is
Atomic Number = number of protons
The number of protons DOES NOT CHANGE!! This would change what element it is!

26. INCREASING REACTIVITY

27. Atomic numbers get bigger as you go to the right and down

28. 2. Electrons The number of electrons determines the charge.
Electrons can be gained or lost from an atom.
They are easy to lose because they are on the outside of the atom and they are VERY SMALL.
Number of protons – Number of electrons = Charge

29. Ion: An atom or a molecule that has a charge
Na loses an e-  Na Atom Ion

30. 3. Neutrons
The number of neutrons helps determine the mass of an atom.
Atomic Mass: the mass of an atom.
# of Protons + # of Neutrons = Atomic Mass

31. Organization of the Periodic Table
In the periodic table elements are listed in order by their atomic number.
Metals are on the left
The transition metals range from group 3 -12
Non-metals are on the right

33. Transition Metals:

34. Metals: Easily LOSE electrons. Metals (left of zig zag line)
Physical Properties of Metals:
shiny
good conductors of heat and electricity
usually SOLIDS at room temperature
Easily LOSE electrons.

35. Properties of Metals: Physical Properties of Metals:
One metal that is not a solid at room temperature is Mercury (Hg)

36. Non-Metals: Easily GAIN electrons Non-metals (right of zig zag line)
Physical Properties of Nonmetals:
dull appearance
poor conductors
Easily GAIN electrons

37. Organization of the Periodic Table
The horizontal rows are called periods

38. The vertical columns are called Families or groups

39. Group 2 = alkaline earth metals Group 17 = the halogens
Elements in a family have similar properties and bond with other elements in similar ways.
Group 1 = alkali metals
Group 2 = alkaline earth metals
Group 17 = the halogens
Group 18 = noble gases 18 1 2 17
(c) McGraw Hill Ryerson 2007

40. Assignment:
BIG BOOK p

41. Chapter 4.1:
Bohr Models

42. Vocabulary:
valence electron
valence shell
stable octet
Bohr model

43. Valence Shells The outside orbital shell is where elements react
Valence Shell: the outside orbital shell
Valence Electrons: the electrons that are in the valence shell
Stable Octet: a full valence shell

44. BOHR MODELS
Bohr diagrams show how many electrons appear in each orbital shell around an atom.
The first electron shell holds 2 electrons
The second electron shell holds 8 electrons
The third electron shell holds 8 electrons
The fourth electron shell holds 18 electrons

45. Bohr Models: The period number = the number of shells
Except for the transition metals (family 3-12),
the last digit of the group number = the
number of electrons in the valence shell.
See page 175
(c) McGraw Hill Ryerson 2007

46. a) Carbon # of shells = # of valence electrons = b) Neon # of shells = c) Magnesium # of shells = d) Iodine # of shells =

47. Bohr Models
In Grade 10, we do not look at Bohr Models for the TRANSITION METALS, or elements with atomic number greater than 20

48. BOHR MODELS How to draw a Bohr Model:
Draw a circle for the nucleus. Write the symbol, the #p and #n in the circle.
2) Draw circles outside the nucleus for the electron shells
3) Draw a dot (or write the #) for each electron in the electron shells.

49. Examples:
Sodium
Phosphorus
Argon

50. BOHR MODELS
What element is this?
18 p
22 n
argon

51. HOMEWORK:
BIG BOOK p
Yellow workbook
p (not #4)

52. Periodic Table and Ion Formation

53. Vocabulary:
cation
anion
stable
reactive

54. Periodic Table & Ion Formation
Atoms gain and lose electrons to form bonds.
Metals lose negative electrons & become positive ions.
Positive ions are called CATIONS.
See page 173
(c) McGraw Hill Ryerson 2007

55. Periodic Table & Ion Formation
Atoms gain and lose electrons to form bonds.
Non-metals gain electrons and become negative ions
Negative ions are called ANIONS
See page 173
(c) McGraw Hill Ryerson 2007

56. Bohr Models - Reactivity
Elements want to be stable
Stable means that the element isn’t affected by other elements
It won’t explode, catch
on fire or react when
combined with other
elements

57. Periodic Table & Ion Formation
Every atom wants to have a stable octet like the nearest noble gas.
Atoms form compounds to get a full valence shell like the closest noble gas in three ways:
Lose electrons (metals) – form cation (+)
Gain electrons (nonmetals) – form anion (-)
Share electrons

58. Group 18: Noble Gases Noble gases (group 18) are STABLE Why??
They have a full valence shell
They don’t form compounds
They don’t react

59. Noble Gases:

60. Bohr Models - Reactivity
Reactive means that the element will react with other elements
Very reactive elements can explode or catch on fire easily

61. Bohr Models - Reactivity
Group 1 elements are the MOST REACTIVE
They even react with water!
-They are reactive because their one valence electron is easy to give up

62. Na metal in water

63. Bohr Models - Reactivity
Example: Na atom and Na ion

64. Bohr Models - Reactivity
Group 2 elements are also reactive
-They want to lose two electrons
-Group 17 elements are VERY REACTIVE
-They want to gain an electron

65. Calcium metal in water:

66. Bohr Models - Reactivity
Example: F atom and F ion

67. Groups and Families
Every atom wants to have a full valence shell like the nearest noble gas.
Atoms can either:
Lose electrons (metals) – + charge, CATION
Gain electrons (non-metals) – - charge, ANION

68. Assignment:
BIG BOOK p

69. Forming Compounds

70. Vocabulary:
ionic compound
covalent compound
Lewis diagram
Diatomic molecule

71. Periodic Table & Ion Formation
Atoms gain and lose electrons to form bonds.
The atoms become ions.
Ions can ATTRACT or REPEL one another.
 + and – attract
 + and + repel
 - and - repel

72. Forming Compounds
When two atoms get close together, their valence electrons react.
valence electrons combine to form a bond
Each atom in the compound wants a full valence shell

73. Forming Compounds  atoms share electrons.
There are 2 types of compounds:
1) IONIC COMPOUND: metal + non-metal
2) COVALENT COMPOUND: non-metal + non-metal
 atoms share electrons.
See pages
(c) McGraw Hill Ryerson 2007

74. Ionic Compounds IONIC COMPOUNDS:
metals lose electrons and non-metals take electrons.
The - and + ions are ATTRACTED to each other and form a BOND.
See pages
(c) McGraw Hill Ryerson 2007

76. Electrons are transferred from the positive ions to negative ions
Ionic Compounds
Example ionic bond:
lithium and oxygen form an ionic bond in the compound Li2O. +
lithium
oxygen
Electrons are transferred from the positive ions to negative ions
Li+ O2- Li+
lithium oxide, Li2O
See pages
(c) McGraw Hill Ryerson 2007

77. Covalent Compounds COVALENT COMPOUND: atoms share electrons.
Covalent bonds form when electrons are shared between two non-metals.
Electrons stay with their atom but are shared
See pages
(c) McGraw Hill Ryerson 2007

80. Covalent Compounds Example covalent bond
Hydrogen and fluorine form a covalent bond in the compound hydrogen fluoride. +
Hydrogen fluoride
hydrogen
fluorine
electrons are shared
(c) McGraw Hill Ryerson 2007
See pages

81. Bohr Models of Compounds:
Ionic Compounds:
Rules:
1) Use square brackets to show the ions
2) Write the charge
Examples:
NaCl LiF2

82. Bohr Models of Compounds:
Covalent Compounds:
Electrons are shared
Examples:
H2O BF3

83. Assignment:
BIG BOOK p

84. Ch. 4.1:
Lewis Diagrams

85. Lewis Diagrams
A Lewis diagrams is simper than a Bohr Diagram. It just shows the valence shell or valence e-.
Dots representing electrons are placed around the element symbols at the points of the compass (north, east, south, and west). N W E S

86. Lewis Diagrams - Basic Rules
Write the symbol for the element
2. Place dots around symbol (● = electron). Place them like the 4 points of a compass.
3. Fill in dots one at a time until the 5th e- is reached, then pair.
Try drawing the Lewis Diagrams for Hydrogen, Fluorine and Nitrogen:

88. Lewis Diagrams

89. Lewis Diagrams of Ions
Lewis diagrams can be used to represent IONS and IONIC BONDS:
For positive ions, one electron dot is removed
For negative ions, one electron dot is added
Square brackets are placed around each ion with the charge
Examples: Li­+ B3+ N3- F-

91. Lewis Diagrams of Ions Lewis diagrams and IONIC Compounds:
Square brackets are placed around each ion with the charge
Example: BeCl2 – 2+ –
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
• • Be Cl Cl Be Cl Cl Be Cl
Each beryllium has two electrons to transfer away, and each chlorine can receive one more electron.
Since Be2+ can donate two electrons and each Cl– can accept only one, two Cl– ions are necessary.
beryllium chloride
See page 179
(c) McGraw Hill Ryerson 2007

92. Lewis Diagrams of Covalent Bonds
Lewis diagrams and COVALENT BONDS:
Valence electrons are drawn for each atom.
Unpaired electrons are shared to form bonds.
One shared pair of electrons = 1 bond (drawn as a line)
See page 179
(c) McGraw Hill Ryerson 2007

93. Lewis Diagrams of Covalent Bonds
Important note:
2 electrons are needed for 1 covalent bond
2 MORE electrons are needed for another covalent bond (a double bond)
(double bond)

94. Lewis Diagrams of Diatomic Molecules
DIATOMIC MOLECULE: Two atoms joined by covalent bonds.
Example: O2 and H2 are also easy to draw as Lewis diagrams.
Diatomic molecules form because they are more stable than atoms by themselves
See page 180
(c) McGraw Hill Ryerson 2007

95. The SEVEN diatomic atoms are:
Br2 I2 Cl2 F2 O2 N2 H2

96. Assignment: Finish the handout (Lewis diagrams), then…
Chapter 4.1 Review in your blue Workbook:
Read p. 57 (from ionic and covalent compounds) to 58. As you read, highlight or underline important terms.
Do the questions on p