1. Chemical Bonding

2. But First… Review!

3. Review Element – a pure form of a substance
Example: Iron, Hydrogen, and Oxygen
Atom – the smallest part of an element that still retains the properties of the element
Compounds – a combination of one or more elements
Example: Water, Salt, and Sugar
H2O NaCl C6H12O6

4. Review 1) How many hydrogen atoms are in the compound 4(C3H8)?
2) How many oxygen atoms are in the compound 2 (CO)?
3) How many manganese atoms are in the compound 5(Mn2O7)?
H atoms = 4 x 8 = 32
O atoms = 2 x 1 = 2
Mn atoms = 2 x 5 = 10

5. Electronegativity the key to understanding different bonds
Electronegativity- the ability of an atom
(and sometimes a group of atoms called a “functional group”)
to attract electrons

6. Electronegativity and Bonding
We can use electronegativity to find out what types of bonds are formed between two atoms.
Each atom has an electronegativity value.
We can find the difference between the values in order to classify whether the bond formed is either ionic or covalent.

8. Electronegativity Values

9. Electronegativity and Bonding
If the difference in electronegativity is between , it is considered a covalent bond.
If the difference is greater than 1.00, then it is considered an ionic bond.
So Which Bond is Stronger?

10. Bonding!

11. 3 Types of Bonding
Covalent Bond
Ionic Bond
Metallic Bond

12. Remember This?

13. Bond Classifications
We can also classify bonds based on the types of atoms involved.
Type of Atom
Bond Classification
2 Non-Metals
Covalent
1 Metal, 1 Non-Metal
Ionic
2 Metals
Metallic

14. Polarity
Polarity occurs when there is a difference in electronegativity between 2 atoms.
This simply means that the electron hangs out around one atom more than the other atom when the two atoms are bonding.
The greater the electronegativity, the more polar the bond is.
Examples: NaCl, H20

15. Polarity of Water

16. Polarity and Bonds Covalent bonds are less polar than ionic bonds.
Ionic bonds are more polar than covalent bonds.
Metallic Bonds are described as a sea of electrons.

17. Quick Quiz: Q: What is electronegativity?
Q: What pattern does electronegativity follow (what/where are the most and least electronegative elements)?
A: The ability of an atom to attract electrons
A: Most electronegative is F at the top right, least is Fr at the bottom left

18. What is a bond?
A bond is a force that holds two or more things together to form a molecule.
What electrons in an atom are involved in bonding?
VALENCE ELECTRONS!

19. Remember valence electrons?
These are the electrons that are orbiting in the valence shell
the ring, or energy level, that is furthest from the nucleus
VALENCE
ELECTRONS ORBIT HERE!

20. So, when we look at bonding..
We are ONLY looking at the outer-most electrons in each atom!

21. Bonding
The combining of elements to form compounds through a shift of electronic structure is known as bonding.
The ultimate goal is to achieve noble gas configuration
To do this elements must gain or lose electrons.
This is achieved through ionic and covalent bonding

22. 3 Types of Bonding
Covalent Bond
Ionic Bond
Metallic Bond

23. The process of forming a compound through the transfer of electrons
Ionic Bonding
The process of forming a compound through the transfer of electrons

24. Or…
A chemical bond that forms between a positively charged ion (cation) and a negatively charged ion (anion).

25. Ionic Bonding
Ionic bonding – bonding that occurs between a metal and non-metal
The electrons are
completely transferred
in ionic bonding
• The result of ionic
bonding are ions

26. Ionic Bonding
In general, metals give up electrons to form cations, and nonmetals accept electrons to form anions

27. Ionic Bonding Activity
The ease with which an element loses or gains electrons is a measure of its activity
Elements in groups IA and VIIA are more active than those in groups IIIA and VA

28. Ionic Bonding
transfer of electron + - Na Cl
NaCl

29. 1s22s22p63s1 Ionic Bonding 1 Electron Neon
Draw the electron configuration for Sodium (Na)
1s22s22p63s1
How many valence electrons does Sodium (Na) have? How many electrons are in the last shell that is unfilled?
1 Electron
If you removed that last electron, which element’s electron configuration would you have?
Neon

30. Ionic Bonding We have a sodium cation!
The sodium atom is no longer neutral because it has lost an electron.
It is now what charge?
It isn’t a neon atom because it still has enough protons to be sodium
An atom that acquires an electrical charge is an ion
If that ion is positive it is a cation
If that ion is negative it is an anion
We have a sodium cation!

31. Ionic Bonding
By losing that valence electron, sodium has accomplished its goal of becoming more stable
This more stable form is of its closest noble gas configuration, neon
It should also be noted
that this new cation has
unique properties of its
own!

32. Ionic Bonding
Anions and cations are held together by opposite charges.
Ionic compounds are called salts.
The bond is formed through the transfer of electrons.
Electrons are transferred to achieve noble gas configuration.

33. Properties of Ionic Bonds
Forms solids (crystal-like structures)
Easily dissolves in water and other polar solvents (conducts electricity)
Have high melting and boiling points
– Forms Crystal Lattice – ordered arrangement

34. Ionic solids are brittle
Strong repulsion breaks crystal apart. + -
Force + - + - + - + -

35. Quick Quiz A: Ionic A: electrons are completely transferred
Q: What type of bonding occurs between a metal and a non metal?
Q: What happens in ionic bonding?
The transfer of electrons creates charged particles called ions
Ions of opposite charges attract
A: Ionic
A: electrons are completely transferred

36. 3 Types of Bonding
Covalent Bond
Ionic Bond
Metallic Bond

37. A chemical bond that results from sharing electrons.
COVALENT BONDS
A chemical bond that results from sharing electrons.
Considered to be part of the outer energy levels of both atoms involved.
Generally occur between atoms that are near each other on the periodic table.
Typically occurs between non-metallic atoms.
A molecule is formed when 2 or more atoms bond COVALENTLY.

38. COVALENT BONDS

39. Covalent Bonding Carbon has 4 electrons in its outermost energy level.
Hydrogen has one electron in its energy level.
If carbon wants to fill its outer energy level it needs 8 electrons.
What will this look like?

40. Everybody is Stable!

41. CO2
Two pairs of electrons are shared between each oxygen atom and carbon.
This gives all 3 atoms 8 electrons = happy

42. Acetylene C2H2
What happens here?

43. Quick Quiz: A: Ions Q: Gaining or losing electrons creates what?
Q: what happens between ions of opposite charges?
Q: What happens when atoms share electrons?
A: Ions
A: They attract
A: They form covalent bonds

44. 3 Types of Bonding
Covalent Bond
Ionic Bond
Metallic Bond

45. METALLIC BONDS
The attraction of a metallic cation for delocalized electrons.
Although metals do have 1 or more valence electrons, they do not share them, NOR do they lose them to other atoms.
They form lattices where the outer energy levels of the metal atoms overlap in an ELECTRON SEA.

46. METALLIC BONDS
Electron sea model

47. METALLIC BONDS
valence electrons of bonding metallic atoms are not held by any specific atom
Electrons able to move easily from one atom to the next.
Since they are free to move they are referred to as DELOCALIZED ELECTRONS.

48. Foldable

49. End Bonding Start Electron Dot Configurations!

50. Keeping Track of Electrons
The electrons that determine chemical properties of atoms are in the outer energy level
Valence electrons - The s and p electrons in the outer energy level.
Core electrons -those in the energy levels below. (not outside level)

51. Atoms in the same column…
Have the same outer electron configuration.
Have the same valence electrons.
Easily found by looking up the group number on the periodic table.
Group 2A - Be, Mg, Ca
2 valence electrons

52. Quick Quiz
Q: which electrons are responsible for the chemical properties of atoms?
Q: what are they called?
Q: What’s so special about elements in the same group or column?
A: Those in the outer energy level
A: Valence electrons
A: Have the same valence electrons

53. X Electron Dot Diagrams A way of keeping track of valence electrons
How to write them:
Write the symbol.
Put one dot for each valence electron
Don’t pair up until they have to X

54. The Electron Dot diagram
for Nitrogen
Nitrogen has 5 valence electrons.
First we write the symbol. N
Then add 1 electron at a time to each side.
Until they are forced to pair up.

55. Write the electron dot diagram for:Na Mg C O F Ne He Na
1s22s22p63s1 Mg
1s22s22p63s2 C
1s22s22p2 O
1s22s22p4 F
1s22s22p5 Ne
1s22s22p6 He
1s2

56. Electron Configurations for Cations
Metals lose electrons to attain noble gas configuration.
They make positive ions.
If we look at electron configuration it makes sense.
Na 1s22s22p63s1 - 1 valence electron
Na+ 1s22s22p6 -noble gas configuration

57. Electron Dots For Cations
Metals will have few valence electrons
These will come off
Forming positive ions Ca
40.078 20
1s22s22p63s2 +2 Ca

58. Electron Configurations for Anions
Nonmetals gain electrons to attain noble gas configuration.
They make negative ions.
If we look at electron configuration it makes sense.
S 1s22s22p63s23p4 - 6 valence electrons
S-2 1s22s22p63s23p6 -noble gas
configuration.
(anions)

59. Electron Dots For Anions
Nonmetals will have many valence electrons.
They will gain electrons to fill outer shell. P
P-3

60. Quick Questions Q: What is the charge of a cation? A: Positive
Q: What is the charge of an anion?
A: Negative
Q: Do metals gain or lose electrons?
A: Lose
Q: Do nonmetals gain or lose electrons?
A: Gain
Q: What are they both trying to achieve?
A: Noble gas configuration, and stability (full outer orbitals)

61. Stable Electron Configurations
All atoms react to achieve noble gas configuration.
Noble gases have two s and six p electrons.
Eight valence electrons
Also called the octet rule. Ar

62. Quick Questions Q: What is an ionic bond?
A: The attraction of oppositely charged ions called cations and anions, which formed from the TRANSFER of electrons
Q: What is another name for ionic compounds?
A: Salts
Q: What do they form from?
A: A metal and a non-metal
Q: What are 3 characteristics of salts?
A: They dissolve in water and other polar solvents, have high melting points, and form crystals

63. Parts of an Ionic Compound
There are two parts associated with an ionic compound:
1) Cation – positive ion (positive oxidation number)
2) Anion – negative ion (negative oxidation number)
NaCl
Cl-
Na+
(Anion)
(Cation)

64. Naming Ionic Compounds
1) Write the name of the cation first.
2) Write the name of the anion second.
3) Change the ending of the anion to have an ending (or suffix) of –ide

65. Naming Ionic Compounds Example
A reaction of Calcium and Chlorine.
- Cation: Calcium = Calcium
- Anion : Chlorine = Chlorine = Chloride
*Calcium Chloride *

66. Common Cations and Anions

67. Naming Ionic Compounds Practice
1) A salt formed by the reaction of Lithium and Chlorine:
2) A salt formed by the reaction of Sodium and Bromine:
3) A compound formed by the reaction of Magnesium and Oxygen:
Lithium Chloride
Sodium Bromide
Magnesium Oxide

68. Salts vs. Oxides
Salt – an ionic bond between a metal and a non-metal other than oxygen
Example: NaBr – Sodium Bromide = Salt
Oxides – an ionic bond between a metal and the non-metal oxygen
-Example: MgO – Magnesium Oxide = Oxide

69. Naming Ionic Compounds Practice
Name the following compounds and identify whether the ionic compound would be considered a salt or an oxide:
1) A reaction between Lithium and Oxygen:
2) A reaction between Sodium and Chlorine:
Lithium Oxide = Oxide
Sodium Chloride = Salt

70. How will I know how many of each cation or anion…?
Look at the periodic table!

71. Monatomic Ions Monatomic ions are one-atom ions
Their charge is determined by their placement on the periodic table!
Remember 8th grade science when your teacher told you that ever atom wants to be like the noble gases?
To get that stable electron configuration, atoms gain or lose electrons
This gaining or losing electrons changes the atoms charge, making them an ion.
Remember an ion is a charged particle!

72. So how do I determine the charge of an ion?
Look at the periodic table!
Group 1A, like lithium, sodium, potassium etc
Do these gain or lose an e- to get to a stable e- configuration?
They lose an e-!
Does this make them positive or negative?
Positive!
How many e- do they lose?
1, so they have an overall charge of +1!

73. The same pattern holds true for period
What about Group 2A?
Atoms like beryllium, Magnesium, Calcium, etc
These lose how many e- to get a stable e- configuration? 2!
So what is the overall charge of monatomic atoms in period 2A? +2
The same pattern holds true for period

74. So what about the other side of the periodic table?
Groups 5A, 6A, and 7A all gain electrons to get a stable electron configuration.
5A gains how many e-, and has what charge?
3, so +3
6A gains how many e-, and has what charge?
2, so +2
7A gains how many e-, and has what charge?
1, so +1

75. Oxidation numbers
The charge of any monatomic ion is called its oxidation number.
Oxidation number is determined by looking at what group an atom is in.
The oxidation numbers of ionic compounds ALWAYS add up to 0!

76. Quick Questions Q: What is a monatomic ion?
A: An ion formed by a SINGLE atom
Q: What is the charge of an ion formed from ANY atom the following groups?
1A, 2A, 3A, 4A, 5A, 6A, and 7A
A: / and -1
Q: What is this charge called?
A: The Oxidation number

77. So what about ionic compounds with more than 2 atoms?
These are called POLYatomic ions
because they contain more than 1 (poly = many) atoms

78. How can you tell by the name?
Ionic and Covalent bonds end with what three letters?
-ide
Polyatomic compounds end with different suffixes…
-ate
-ite

79. Transition Metals
Those silly (we all dislike these) metals in the middle of periodic table
Lots of valuable metals here though…..gold, silver, nickel, copper, platinum…..
These are ALWAYS Cations in bonding with other elements.

80. (I), (II), (III), or (IV)? Use back of periodic table
Notice charges of the different Cations….
If positive, wants to give away that many electrons. If negative, wants to gain that many….just like the front of the periodic table
Ex….Copper (II)…..Co +2…..wants to give away 2 electrons…..so if it pairs up with nitrogen, what is the formula?

81. Copper (II) + Nitrogen What’s the name? Copper (ii) Nitride
Copper (II) has +2 charge
Nitrogen has -3 charge
How can we tell the formula?
Look for common denominators…..2 and 3?
How many 2’s to make 6? How many 3’s?
That’s the formula now…..

82. Ca +2 Ca P -3 +2 Ca P -3 +2 Ionic Bonding
All the electrons must be accounted for!

83. Ca2+ Ca3P2 Ca2+ P3- Ca2+ P3- Ionic Bonding Formula Unit Ca2+ P3- Ca2+

84. Helpful Video!

85. Practice ionic compound questions
1) How many lithium ions and chlorine ions would combine to make a stable ionic compound?
1 of each because Li has a +1 charge, and Cl has a -1 charge
Formula = LiCl
2) How many magnesium ions and chlorine ions would combine to make a stable ionic compound?
1 Mg and 2 Cl because Mg has a charge of +2, and Cl has a charge of -1
Formula = MgCl2

86. Binary Covalent Compounds
First Element
Second Element
Write the correct prefix to show how many of that element you have
If it is only 1 – don’t write anything
Simply write out the element’s name
Again, write the correct prefix to show how many of that element you have
Do write mono!
Write the name of your element
Take off the ending and write –ide

87. Prefixes

88. Examples
SiH4
Silicon Tetrahydride
CO2
Carbon Dioxide

89. Polyatomic Ions
A polyatomic ion is a molecule made up of 2 or more atoms that bears ionic groups, that is, a molecule with a charge.
Examples include:
NO3 nitrate
ClO chlorate

90. Nomenclature with Polyatomic Ions
The same rules apply, except that you add in the correct name for the polyatomic ion
Memorize/use your common polyatomic ions in order to correctly name the compounds

91. Common Polyatomic Ions

92. Ate and Ite
_____ate means that all of the oxygen atoms possible are bonded
____ite means that there is one less oxygen bonded

93. Example Naming with Polyatomic Ions
NaNO2
Sodium Nitrite