1. Chemistry Unit 4: Bonding
Essential question: How are electrons arranged in orbitals?

2. Where are electrons found?
Electrons do not travel in specific orbits as in Bohr’s Model of the atom
Instead, they travel within the atomic orbitals

3. What are atomic orbitals?
These are regions where there is a high probability of finding an electron
Each atomic orbital has a principal energy level denoted by the letter, (n).

4. Principal Energy Levels can be broken down into Sublevels with different shapes called orbitals.

5. Electrons in atoms are arranged as:
Summary
Electrons in atoms are arranged as:
LEVELS (n)
SUBLEVELS
ORBITALS

6. Sublevels are written as
1s, 2s, 2p…….

7. What are the 4 types of orbitals?
There are the s, p, d and f orbital.

8. S orbitals Spherical shaped # of s orbitals: 1
Can hold a max. of 2 electrons

9. P orbitals # of p orbitals: 3 Dumbbell shaped
Can hold a maximum of 6 electrons

10. The d sublevel contains 5 D orbitals
The d sublevel starts in the 3rd energy level
5 different orbitals
Can hold a max. of 10 electrons

11. The f sublevel has 7 F orbitals
The F sublevel starts in the fourth energy level
seven different orbitals
Can hold a max of 14 electrons

12. Electrons in atoms are arranged as:
Summary
Electrons in atoms are arranged as:
LEVELS (n)
SUBLEVELS
ORBITALS

13. Summary 2 6 10 14 s p d f 1 3 5 7 Maximum electrons
# of shapes (orbitals)
Starts at energy level
#of pigs
Rooms in Hotel 2 s 1 1 p 3 6 2 10 d 5 3 7 14 4 f

14. How are electrons filled in orbitals?
There are three rules to follow:
Aufbau principle - electrons enter the lowest energy first.
Hund’s Rule- electrons don’t pair up until they absolutely have to.
Pauli Exclusion Principle - at most 2 electrons per orbital. If they must pair up they have different spins (face opposite directions).

15. So how do we write this?
We use an orbital diagram.

16. So how do we write this?
It can also be written in a straight line just like your Hog Hilton activity
Like this,
1s 2s p s p

17. How do we know which sublevel to place an electron in?
You must determine how many electrons to fill in your orbitals. Use the periodic table, of course! And the three electron filling rules!

18. s p d f 1 2 3 4 5 6 7 1A 2A 3B 4B 5B 6B 7B 8B 1B 2B 3A 4A 5A 6A 7A 8A
Row =
# shells d f

20. # of electrons in orbital
Orbital Diagrams 1s
Period #
# of electrons in orbital
subshell
possibilities are
s, p, d, or f

21. Example
Orbital diagram of Carbon

22. Lets try Neon together!

23. On your own,
Draw the orbital diagram for Sulfur

24. Work with a partner!
Draw the orbital diagram for Potassium.

25. Work with a partner!
Draw the orbital diagram for Nickel.

26. It is called electron configuration
Easier way?
It is called electron configuration

27. Describe how to write the electron configuration for an atom.
OBJECTIVES:
Describe how to write the electron configuration for an atom.

28. s p d f 1 2 3 4 5 6 7 1A 2A 3B 4B 5B 6B 7B 8B 1B 2B 3A 4A 5A 6A 7A 8A
Row =
# shells d f

29. Electron Configuration
1s1
possibilities are:
s: 1 or 2
p: 1-6
d: 1-10
f: 1-14
Period #
subshell
possibilities are
s, p, d, or f
What element has an electron configuration of 1s1?

30. For example, Orbital diagram of carbon
Electron configuration of Carbon is 1s²2s²2p²
Simply count electrons as you fill each orbital!

31. Let’s Practice together
Let’s write the electron configuration for Phosphorus
1s²2s²2p⁶3s²3p³

32. On your own,
Write the electron configuration for Calcium 1s²2s²2p⁶3s²3p⁶4s²

33. On your own,
Write the electron configuration for Iron 1s²2s²2p⁶3s²3p⁶4s²3d⁶

34. Which element is this?
The total number of electrons at the top helps you to identify the element!

35. With an elbow buddy, complete
The Electron Configuration Station Activity

36. Warm Up Give the Lewis Dot Structure for the following: Chlorine
Calcium
Gallium
Carbon
Sulfur

37. What is the “ground state” of an atom?
This is the normal electron configuration of atoms. This is the most stable state for electrons

38. What is the “excited state” of an atom?
This happens when electrons are heated and they absorb the heat energy. Because of the extra energy, electrons are able to ‘jump’ to higher energy levels. This is known as the “excited state”.

39. What happens in the “excited state”?
In this state, electrons are unstable, so they fall back to their lower energy levels. As they return to their lower energy level, the energy absorbed gets released as light. The visible light is called a photon or a quanta of light.

40. Photons?
The color of this photon is used to identify elements. Such analysis is done using a Flame Test.

41. What is the electron emission spectrum?
The color emitted by each element can be used to identify an element, similar to a fingerprint.

42. What are valence electrons?
What is the octet rule?

43. Valence Electrons
Valence electrons are the electrons located in the outermost orbit
Elements become stable when:
their outer orbit contains 8 electrons or their outer orbit becomes empty
Lewis Dot Diagrams show the # of Valence Electrons

44. Octet Rule?
Atoms can gain, lose, or share electrons until they have eight valence electrons.

45. Part 2:Essential questions:
Why do atoms bond?
How are bonds formed?

46. Forces that hold groups of atoms together and make them function as a unit.
What are bonds?

47. What are the two main types of bonds?
Ionic bonds
2) Covalent bonds

48. What are Ionic bonds? Form between a metal and a nonmetal
Metals transfer electrons to the non-metal

49. Ionic bond video clip

50. What are the properties of ionic compounds?
High melting points
High boiling points
Conduct electric current when dissolved in solution
Difficult to break

51. For example

52. Ionic Bonds
What is the formula for the compound that forms between magnesium and chlorine? Cl
· · Mg
· · Cl
· ·
MgCl2
NaCl

53. Warm Up Give the electron configuration for Strontium
What is an Ionic Bond?

54. Ionic bonds?
After bonding, each atom has a full outermost shell with eight valence electrons Except Hydrogen, which needs two valance electrons to be stable and happy!

55. What are Covalent bonds?
This is a bond between two Nonmetals.
They share valence electrons with each other.
By sharing, both atoms obtain eight valence electrons.
They do not give away electrons to bond.

56. Covalent bonding video clip

57. How many valence electrons does Fluorine have?
Fluorine has seven valence electrons F

58. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven F F

59. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons…
…both end with full orbitals and eight valence electrons F F
8 Valence electrons

60. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons…
…both end with full orbitals F F
8 Valence electrons

61. How do we know a compound is covalent?
Two non-metals bonded together
Low melting and boiling points
Commonly referred to as Molecular Compounds.

62. H O Water Each hydrogen has 1 valence electron
Each hydrogen wants 1 more
The oxygen has 6 valence electrons
The oxygen wants 2 more
They share to make each other complete O

63. H O H Water A second hydrogen attaches
Every atom has full energy levels
Note the two “unshared” pairs of electrons H O H

64. What is the formula for Water?
Use the Lewis Dot diagram
H2O

65. How do we show 2 atoms sharing?
We use a line
It is called a single bond
Only one pair of electrons are shared

66. Sometimes more than one pair of electrons are shared to obtain a full outermost orbit

67. What if 2 pairs of electrons are shared?
We use 2 lines O2

68. 3 electron pairs?
We use three lines N2

69. What is a lone pair?
These are the pairs of electrons that are not involved in bonding

70. What is the central atom?
The least electronegative atom
The atom that is placed in the center

71. Warm Up
What is a Covalent molecule?

72. What are the shapes of covalent bonds?
Linear
Bent
Trigonal Planar
Tetrahedral
Pyramidal

73. Linear? All electrons in the central atom are bonded
Everything is in a straight line

74. Bent?
There are 2 pairs of lone pairs on the central atom

75. Trigonal Planar?
3 atoms bonded to the central atom

76. Pyramidal?
One lone pair and three bonded sides

77. Tetrahedral?
Four bonded sides around the central atom
No lone pairs

78. How to predict the shape of a molecule?
Step 1: Draw the Lewis Dot structure for each atom Step 2: Arrange the elements so that each atom will have a full outmost shell Step 3: Count the number of bonds and lone pairs (if any).

79. Step 1: Lewis Dot Structure
Let’s try together! NH3
Step 1: Lewis Dot Structure
Step 2: Arrange atoms
Step 3: Count the number of bonds and lone pairs
3 bonds and one lone pair
Pyramidal

80. On your own
Predict the shape of CH4
Tetrahedral

81. With a partner!
Predict the shape of
H2S
CCl4
CHCl3

82. What is a polar molecule?
A molecule where electrons are shared unequally.
What is a Non-polar molecule?
A molecule where electrons are shared equally.

83. How do we know if a molecule is polar?
If the central atom has LONE pairs, it is a POLAR molecule

84. How do we know if a molecule is non-polar?
If there are NO lone pairs present on the central molecule, it is NON-POLAR.

85. Exit ticket
Predict the shape of BF3