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Raffi Hovasapian

Raffi Hovasapian

Electron Configurations & Diagrams

Slide Duration:

Table of Contents

I. Review
Naming Compounds

41m 24s

Intro
0:00
Periodic Table of Elements
0:15
Naming Compounds
3:13
Definition and Examples of Ions
3:14
Ionic (Symbol to Name): NaCl
5:23
Ionic (Name to Symbol): Calcium Oxide
7:58
Ionic - Polyatoms Anions: Examples
12:45
Ionic - Polyatoms Anions (Symbol to Name): KClO
14:50
Ionic - Polyatoms Anions (Name to Symbol): Potassium Phosphate
15:49
Ionic Compounds Involving Transition Metals (Symbol to Name): Co₂(CO₃)₃
20:48
Ionic Compounds Involving Transition Metals (Name to Symbol): Palladium 2 Acetate
22:44
Naming Covalent Compounds (Symbol to Name): CO
26:21
Naming Covalent Compounds (Name to Symbol): Nitrogen Trifluoride
27:34
Naming Covalent Compounds (Name to Symbol): Dichlorine Monoxide
27:57
Naming Acids Introduction
28:11
Naming Acids (Name to Symbol): Chlorous Acid
35:08
% Composition by Mass Example
37:38
Stoichiometry

37m 19s

Intro
0:00
Stoichiometry
0:25
Introduction to Stoichiometry
0:26
Example 1
5:03
Example 2
10:17
Example 3
15:09
Example 4
24:02
Example 5: Questions
28:11
Example 5: Part A - Limiting Reactant
30:30
Example 5: Part B
32:27
Example 5: Part C
35:00
II. Aqueous Reactions & Stoichiometry
Precipitation Reactions

31m 14s

Intro
0:00
Precipitation Reactions
0:53
Dissociation of ionic Compounds
0:54
Solubility Guidelines for ionic Compounds: Soluble Ionic Compounds
8:15
Solubility Guidelines for ionic Compounds: Insoluble ionic Compounds
12:56
Precipitation Reactions
14:08
Example 1: Mixing a Solution of BaCl₂ & K₂SO₄
21:21
Example 2: Mixing a Solution of Mg(NO₃)₂ & KI
26:10
Acid-Base Reactions

43m 21s

Intro
0:00
Acid-Base Reactions
1:00
Introduction to Acid: Monoprotic Acid and Polyprotic Acid
1:01
Introduction to Base
8:28
Neutralization
11:45
Example 1
16:17
Example 2
21:55
Molarity
24:50
Example 3
26:50
Example 4
30:01
Example 4: Limiting Reactant
37:51
Example 4: Reaction Part
40:01
Oxidation Reduction Reactions

47m 58s

Intro
0:00
Oxidation Reduction Reactions
0:26
Oxidation and Reduction Overview
0:27
How Can One Tell Whether Oxidation-Reduction has Taken Place?
7:13
Rules for Assigning Oxidation State: Number 1
11:22
Rules for Assigning Oxidation State: Number 2
12:46
Rules for Assigning Oxidation State: Number 3
13:25
Rules for Assigning Oxidation State: Number 4
14:50
Rules for Assigning Oxidation State: Number 5
15:41
Rules for Assigning Oxidation State: Number 6
17:00
Example 1: Determine the Oxidation State of Sulfur in the Following Compounds
18:20
Activity Series and Reduction Properties
25:32
Activity Series and Reduction Properties
25:33
Example 2: Write the Balance Molecular, Total Ionic, and Net Ionic Equations for Al + HCl
31:37
Example 3
34:25
Example 4
37:55
Stoichiometry Examples

31m 50s

Intro
0:00
Stoichiometry Example 1
0:36
Example 1: Question and Answer
0:37
Stoichiometry Example 2
6:57
Example 2: Questions
6:58
Example 2: Part A Solution
12:16
Example 2: Part B Solution
13:05
Example 2: Part C Solution
14:00
Example 2: Part D Solution
14:38
Stoichiometry Example 3
17:56
Example 3: Questions
17:57
Example 3: Part A Solution
19:51
Example 3: Part B Solution
21:43
Example 3: Part C Solution
26:46
III. Gases
Pressure, Gas Laws, & The Ideal Gas Equation

49m 40s

Intro
0:00
Pressure
0:22
Pressure Overview
0:23
Torricelli: Barometer
4:35
Measuring Gas Pressure in a Container
7:49
Boyle's Law
12:40
Example 1
16:56
Gas Laws
21:18
Gas Laws
21:19
Avogadro's Law
26:16
Example 2
31:47
Ideal Gas Equation
38:20
Standard Temperature and Pressure (STP)
38:21
Example 3
40:43
Partial Pressure, Mol Fraction, & Vapor Pressure

32m

Intro
0:00
Gases
0:27
Gases
0:28
Mole Fractions
5:52
Vapor Pressure
8:22
Example 1
13:25
Example 2
22:45
Kinetic Molecular Theory and Real Gases

31m 58s

Intro
0:00
Kinetic Molecular Theory and Real Gases
0:45
Kinetic Molecular Theory 1
0:46
Kinetic Molecular Theory 2
4:23
Kinetic Molecular Theory 3
5:42
Kinetic Molecular Theory 4
6:27
Equations
7:52
Effusion
11:15
Diffusion
13:30
Example 1
19:54
Example 2
23:23
Example 3
26:45
AP Practice for Gases

25m 34s

Intro
0:00
Example 1
0:34
Example 1
0:35
Example 2
6:15
Example 2: Part A
6:16
Example 2: Part B
8:46
Example 2: Part C
10:30
Example 2: Part D
11:15
Example 2: Part E
12:20
Example 2: Part F
13:22
Example 3
14:45
Example 3
14:46
Example 4
18:16
Example 4
18:17
Example 5
21:04
Example 5
21:05
IV. Thermochemistry
Energy, Heat, and Work

37m 32s

Intro
0:00
Thermochemistry
0:25
Temperature and Heat
0:26
Work
3:07
System, Surroundings, Exothermic Process, and Endothermic Process
8:19
Work & Gas: Expansion and Compression
16:30
Example 1
24:41
Example 2
27:47
Example 3
31:58
Enthalpy & Hess's Law

32m 34s

Intro
0:00
Thermochemistry
1:43
Defining Enthalpy & Hess's Law
1:44
Example 1
6:48
State Function
13:11
Example 2
17:15
Example 3
24:09
Standard Enthalpies of Formation

23m 9s

Intro
0:00
Thermochemistry
1:04
Standard Enthalpy of Formation: Definition & Equation
1:05
∆H of Formation
10:00
Example 1
11:22
Example 2
19:00
Calorimetry

39m 28s

Intro
0:00
Thermochemistry
0:21
Heat Capacity
0:22
Molar Heat Capacity
4:44
Constant Pressure Calorimetry
5:50
Example 1
12:24
Constant Volume Calorimetry
21:54
Example 2
24:40
Example 3
31:03
V. Kinetics
Reaction Rates and Rate Laws

36m 24s

Intro
0:00
Kinetics
2:18
Rate: 2 NO₂ (g) → 2NO (g) + O₂ (g)
2:19
Reaction Rates Graph
7:25
Time Interval & Average Rate
13:13
Instantaneous Rate
15:13
Rate of Reaction is Proportional to Some Power of the Reactant Concentrations
23:49
Example 1
27:19
Method of Initial Rates

30m 48s

Intro
0:00
Kinetics
0:33
Rate
0:34
Idea
2:24
Example 1: NH₄⁺ + NO₂⁻ → NO₂ (g) + 2 H₂O
5:36
Example 2: BrO₃⁻ + 5 Br⁻ + 6 H⁺ → 3 Br₂ + 3 H₂O
19:29
Integrated Rate Law & Reaction Half-Life

32m 17s

Intro
0:00
Kinetics
0:52
Integrated Rate Law
0:53
Example 1
6:26
Example 2
15:19
Half-life of a Reaction
20:40
Example 3: Part A
25:41
Example 3: Part B
28:01
Second Order & Zero-Order Rate Laws

26m 40s

Intro
0:00
Kinetics
0:22
Second Order
0:23
Example 1
6:08
Zero-Order
16:36
Summary for the Kinetics Associated with the Reaction
21:27
Activation Energy & Arrhenius Equation

40m 59s

Intro
0:00
Kinetics
0:53
Rate Constant
0:54
Collision Model
2:45
Activation Energy
5:11
Arrhenius Proposed
9:54
2 Requirements for a Successful Reaction
15:39
Rate Constant
17:53
Arrhenius Equation
19:51
Example 1
25:00
Activation Energy & the Values of K
32:12
Example 2
36:46
AP Practice for Kinetics

29m 8s

Intro
0:00
Kinetics
0:43
Example 1
0:44
Example 2
6:53
Example 3
8:58
Example 4
11:36
Example 5
16:36
Example 6: Part A
21:00
Example 6: Part B
25:09
VI. Equilibrium
Equilibrium, Part 1

46m

Intro
0:00
Equilibrium
1:32
Introduction to Equilibrium
1:33
Equilibrium Rules
14:00
Example 1: Part A
16:46
Example 1: Part B
18:48
Example 1: Part C
22:13
Example 1: Part D
24:55
Example 2: Part A
27:46
Example 2: Part B
31:22
Example 2: Part C
33:00
Reverse a Reaction
36:04
Example 3
37:24
Equilibrium, Part 2

40m 53s

Intro
0:00
Equilibrium
1:31
Equilibriums Involving Gases
1:32
General Equation
10:11
Example 1: Question
11:55
Example 1: Answer
13:43
Example 2: Question
19:08
Example 2: Answer
21:37
Example 3: Question
33:40
Example 3: Answer
35:24
Equilibrium: Reaction Quotient

45m 53s

Intro
0:00
Equilibrium
0:57
Reaction Quotient
0:58
If Q > K
5:37
If Q < K
6:52
If Q = K
7:45
Example 1: Part A
8:24
Example 1: Part B
13:11
Example 2: Question
20:04
Example 2: Answer
22:15
Example 3: Question
30:54
Example 3: Answer
32:52
Steps in Solving Equilibrium Problems
42:40
Equilibrium: Examples

31m 51s

Intro
0:00
Equilibrium
1:09
Example 1: Question
1:10
Example 1: Answer
4:15
Example 2: Question
13:04
Example 2: Answer
15:20
Example 3: Question
25:03
Example 3: Answer
26:32
Le Chatelier's principle & Equilibrium

40m 52s

Intro
0:00
Le Chatelier
1:05
Le Chatelier Principle
1:06
Concentration: Add 'x'
5:25
Concentration: Subtract 'x'
7:50
Example 1
9:44
Change in Pressure
12:53
Example 2
20:40
Temperature: Exothermic and Endothermic
24:33
Example 3
29:55
Example 4
35:30
VII. Acids & Bases
Acids and Bases

50m 11s

Intro
0:00
Acids and Bases
1:14
Bronsted-Lowry Acid-Base Model
1:28
Reaction of an Acid with Water
4:36
Acid Dissociation
10:51
Acid Strength
13:48
Example 1
21:22
Water as an Acid & a Base
25:25
Example 2: Part A
32:30
Example 2: Part B
34:47
Example 3: Part A
35:58
Example 3: Part B
39:33
pH Scale
41:12
Example 4
43:56
pH of Weak Acid Solutions

43m 52s

Intro
0:00
pH of Weak Acid Solutions
1:12
pH of Weak Acid Solutions
1:13
Example 1
6:26
Example 2
14:25
Example 3
24:23
Example 4
30:38
Percent Dissociation: Strong & Weak Bases

43m 4s

Intro
0:00
Bases
0:33
Percent Dissociation: Strong & Weak Bases
0:45
Example 1
6:23
Strong Base Dissociation
11:24
Example 2
13:02
Weak Acid and General Reaction
17:38
Example: NaOH → Na⁺ + OH⁻
20:30
Strong Base and Weak Base
23:49
Example 4
24:54
Example 5
33:51
Polyprotic Acids

35m 34s

Intro
0:00
Polyprotic Acids
1:04
Acids Dissociation
1:05
Example 1
4:51
Example 2
17:30
Example 3
31:11
Salts and Their Acid-Base Properties

41m 14s

Intro
0:00
Salts and Their Acid-Base Properties
0:11
Salts and Their Acid-Base Properties
0:15
Example 1
7:58
Example 2
14:00
Metal Ion and Acidic Solution
22:00
Example 3
28:35
NH₄F → NH₄⁺ + F⁻
34:05
Example 4
38:03
Common Ion Effect & Buffers

41m 58s

Intro
0:00
Common Ion Effect & Buffers
1:16
Covalent Oxides Produce Acidic Solutions in Water
1:36
Ionic Oxides Produce Basic Solutions in Water
4:15
Practice Example 1
6:10
Practice Example 2
9:00
Definition
12:27
Example 1: Part A
16:49
Example 1: Part B
19:54
Buffer Solution
25:10
Example of Some Buffers: HF and NaF
30:02
Example of Some Buffers: Acetic Acid & Potassium Acetate
31:34
Example of Some Buffers: CH₃NH₂ & CH₃NH₃Cl
33:54
Example 2: Buffer Solution
36:36
Buffer

32m 24s

Intro
0:00
Buffers
1:20
Buffer Solution
1:21
Adding Base
5:03
Adding Acid
7:14
Example 1: Question
9:48
Example 1: Recall
12:08
Example 1: Major Species Upon Addition of NaOH
16:10
Example 1: Equilibrium, ICE Chart, and Final Calculation
24:33
Example 1: Comparison
29:19
Buffers, Part II

40m 6s

Intro
0:00
Buffers
1:27
Example 1: Question
1:32
Example 1: ICE Chart
3:15
Example 1: Major Species Upon Addition of OH⁻, But Before Rxn
7:23
Example 1: Equilibrium, ICE Chart, and Final Calculation
12:51
Summary
17:21
Another Look at Buffering & the Henderson-Hasselbalch equation
19:00
Example 2
27:08
Example 3
32:01
Buffers, Part III

38m 43s

Intro
0:00
Buffers
0:25
Buffer Capacity Part 1
0:26
Example 1
4:10
Buffer Capacity Part 2
19:29
Example 2
25:12
Example 3
32:02
Titrations: Strong Acid and Strong Base

42m 42s

Intro
0:00
Titrations: Strong Acid and Strong Base
1:11
Definition of Titration
1:12
Sample Problem
3:33
Definition of Titration Curve or pH Curve
9:46
Scenario 1: Strong Acid- Strong Base Titration
11:00
Question
11:01
Part 1: No NaOH is Added
14:00
Part 2: 10.0 mL of NaOH is Added
15:50
Part 3: Another 10.0 mL of NaOH & 20.0 mL of NaOH are Added
22:19
Part 4: 50.0 mL of NaOH is Added
26:46
Part 5: 100.0 mL (Total) of NaOH is Added
27:26
Part 6: 150.0 mL (Total) of NaOH is Added
32:06
Part 7: 200.0 mL of NaOH is Added
35:07
Titrations Curve for Strong Acid and Strong Base
35:43
Titrations: Weak Acid and Strong Base

42m 3s

Intro
0:00
Titrations: Weak Acid and Strong Base
0:43
Question
0:44
Part 1: No NaOH is Added
1:54
Part 2: 10.0 mL of NaOH is Added
5:17
Part 3: 25.0 mL of NaOH is Added
14:01
Part 4: 40.0 mL of NaOH is Added
21:55
Part 5: 50.0 mL (Total) of NaOH is Added
22:25
Part 6: 60.0 mL (Total) of NaOH is Added
31:36
Part 7: 75.0 mL (Total) of NaOH is Added
35:44
Titration Curve
36:09
Titration Examples & Acid-Base Indicators

52m 3s

Intro
0:00
Examples and Indicators
0:25
Example 1: Question
0:26
Example 1: Solution
2:03
Example 2: Question
12:33
Example 2: Solution
14:52
Example 3: Question
23:45
Example 3: Solution
25:09
Acid/Base Indicator Overview
34:45
Acid/Base Indicator Example
37:40
Acid/Base Indicator General Result
47:11
Choosing Acid/Base Indicator
49:12
VIII. Solubility
Solubility Equilibria

36m 25s

Intro
0:00
Solubility Equilibria
0:48
Solubility Equilibria Overview
0:49
Solubility Product Constant
4:24
Definition of Solubility
9:10
Definition of Solubility Product
11:28
Example 1
14:09
Example 2
20:19
Example 3
27:30
Relative Solubilities
31:04
Solubility Equilibria, Part II

42m 6s

Intro
0:00
Solubility Equilibria
0:46
Common Ion Effect
0:47
Example 1
3:14
pH & Solubility
13:00
Example of pH & Solubility
15:25
Example 2
23:06
Precipitation & Definition of the Ion Product
26:48
If Q > Ksp
29:31
If Q < Ksp
30:27
Example 3
32:58
Solubility Equilibria, Part III

43m 9s

Intro
0:00
Solubility Equilibria
0:55
Example 1: Question
0:56
Example 1: Step 1 - Check to See if Anything Precipitates
2:52
Example 1: Step 2 - Stoichiometry
10:47
Example 1: Step 3 - Equilibrium
16:34
Example 2: Selective Precipitation (Question)
21:02
Example 2: Solution
23:41
Classical Qualitative Analysis
29:44
Groups: 1-5
38:44
IX. Complex Ions
Complex Ion Equilibria

43m 38s

Intro
0:00
Complex Ion Equilibria
0:32
Complex Ion
0:34
Ligan Examples
1:51
Ligand Definition
3:12
Coordination
6:28
Example 1
8:08
Example 2
19:13
Complex Ions & Solubility

31m 30s

Intro
0:00
Complex Ions and Solubility
0:23
Recall: Classical Qualitative Analysis
0:24
Example 1
6:10
Example 2
16:16
Dissolving a Water-Insoluble Ionic Compound: Method 1
23:38
Dissolving a Water-Insoluble Ionic Compound: Method 2
28:13
X. Chemical Thermodynamics
Spontaneity, Entropy, & Free Energy, Part I

56m 28s

Intro
0:00
Spontaneity, Entropy, Free Energy
2:25
Energy Overview
2:26
Equation: ∆E = q + w
4:30
State Function/ State Property
8:35
Equation: w = -P∆V
12:00
Enthalpy: H = E + PV
14:50
Enthalpy is a State Property
17:33
Exothermic and Endothermic Reactions
19:20
First Law of Thermodynamic
22:28
Entropy
25:48
Spontaneous Process
33:53
Second Law of Thermodynamic
36:51
More on Entropy
42:23
Example
43:55
Spontaneity, Entropy, & Free Energy, Part II

39m 55s

Intro
0:00
Spontaneity, Entropy, Free Energy
1:30
∆S of Universe = ∆S of System + ∆S of Surrounding
1:31
Convention
3:32
Examining a System
5:36
Thermodynamic Property: Sign of ∆S
16:52
Thermodynamic Property: Magnitude of ∆S
18:45
Deriving Equation: ∆S of Surrounding = -∆H / T
20:25
Example 1
25:51
Free Energy Equations
29:22
Spontaneity, Entropy, & Free Energy, Part III

30m 10s

Intro
0:00
Spontaneity, Entropy, Free Energy
0:11
Example 1
2:38
Key Concept of Example 1
14:06
Example 2
15:56
Units for ∆H, ∆G, and S
20:56
∆S of Surrounding & ∆S of System
22:00
Reaction Example
24:17
Example 3
26:52
Spontaneity, Entropy, & Free Energy, Part IV

30m 7s

Intro
0:00
Spontaneity, Entropy, Free Energy
0:29
Standard Free Energy of Formation
0:58
Example 1
4:34
Reaction Under Non-standard Conditions
13:23
Example 2
16:26
∆G = Negative
22:12
∆G = 0
24:38
Diagram Example of ∆G
26:43
Spontaneity, Entropy, & Free Energy, Part V

44m 56s

Intro
0:00
Spontaneity, Entropy, Free Energy
0:56
Equations: ∆G of Reaction, ∆G°, and K
0:57
Example 1: Question
6:50
Example 1: Part A
9:49
Example 1: Part B
15:28
Example 2
17:33
Example 3
23:31
lnK = (- ∆H° ÷ R) ( 1 ÷ T) + ( ∆S° ÷ R)
31:36
Maximum Work
35:57
XI. Electrochemistry
Oxidation-Reduction & Balancing

39m 23s

Intro
0:00
Oxidation-Reduction and Balancing
2:06
Definition of Electrochemistry
2:07
Oxidation and Reduction Review
3:05
Example 1: Assigning Oxidation State
10:15
Example 2: Is the Following a Redox Reaction?
18:06
Example 3: Step 1 - Write the Oxidation & Reduction Half Reactions
22:46
Example 3: Step 2 - Balance the Reaction
26:44
Example 3: Step 3 - Multiply
30:11
Example 3: Step 4 - Add
32:07
Example 3: Step 5 - Check
33:29
Galvanic Cells

43m 9s

Intro
0:00
Galvanic Cells
0:39
Example 1: Balance the Following Under Basic Conditions
0:40
Example 1: Steps to Balance Reaction Under Basic Conditions
3:25
Example 1: Solution
5:23
Example 2: Balance the Following Reaction
13:56
Galvanic Cells
18:15
Example 3: Galvanic Cells
28:19
Example 4: Galvanic Cells
35:12
Cell Potential

48m 41s

Intro
0:00
Cell Potential
2:08
Definition of Cell Potential
2:17
Symbol and Unit
5:50
Standard Reduction Potential
10:16
Example Figure 1
13:08
Example Figure 2
19:00
All Reduction Potentials are Written as Reduction
23:10
Cell Potential: Important Fact 1
26:49
Cell Potential: Important Fact 2
27:32
Cell Potential: Important Fact 3
28:54
Cell Potential: Important Fact 4
30:05
Example Problem 1
32:29
Example Problem 2
38:38
Potential, Work, & Free Energy

41m 23s

Intro
0:00
Potential, Work, Free Energy
0:42
Descriptions of Galvanic Cell
0:43
Line Notation
5:33
Example 1
6:26
Example 2
11:15
Example 3
15:18
Equation: Volt
22:20
Equations: Cell Potential, Work, and Charge
28:30
Maximum Cell Potential is Related to the Free Energy of the Cell Reaction
35:09
Example 4
37:42
Cell Potential & Concentration

34m 19s

Intro
0:00
Cell Potential & Concentration
0:29
Example 1: Question
0:30
Example 1: Nernst Equation
4:43
Example 1: Solution
7:01
Cell Potential & Concentration
11:27
Example 2
16:38
Manipulating the Nernst Equation
25:15
Example 3
28:43
Electrolysis

33m 21s

Intro
0:00
Electrolysis
3:16
Electrolysis: Part 1
3:17
Electrolysis: Part 2
5:25
Galvanic Cell Example
7:13
Nickel Cadmium Battery
12:18
Ampere
16:00
Example 1
20:47
Example 2
25:47
XII. Light
Light

44m 45s

Intro
0:00
Light
2:14
Introduction to Light
2:15
Frequency, Speed, and Wavelength of Waves
3:58
Units and Equations
7:37
Electromagnetic Spectrum
12:13
Example 1: Calculate the Frequency
17:41
E = hν
21:30
Example 2: Increment of Energy
25:12
Photon Energy of Light
28:56
Wave and Particle
31:46
Example 3: Wavelength of an Electron
34:46
XIII. Quantum Mechanics
Quantum Mechanics & Electron Orbitals

54m

Intro
0:00
Quantum Mechanics & Electron Orbitals
0:51
Quantum Mechanics & Electron Orbitals Overview
0:52
Electron Orbital and Energy Levels for the Hydrogen Atom
8:47
Example 1
13:41
Quantum Mechanics: Schrodinger Equation
19:19
Quantum Numbers Overview
31:10
Principal Quantum Numbers
33:28
Angular Momentum Numbers
34:55
Magnetic Quantum Numbers
36:35
Spin Quantum Numbers
37:46
Primary Level, Sublevels, and Sub-Sub-Levels
39:42
Example
42:17
Orbital & Quantum Numbers
49:32
Electron Configurations & Diagrams

34m 4s

Intro
0:00
Electron Configurations & Diagrams
1:08
Electronic Structure of Ground State Atom
1:09
Order of Electron Filling
3:50
Electron Configurations & Diagrams: H
8:41
Electron Configurations & Diagrams: He
9:12
Electron Configurations & Diagrams: Li
9:47
Electron Configurations & Diagrams: Be
11:17
Electron Configurations & Diagrams: B
12:05
Electron Configurations & Diagrams: C
13:03
Electron Configurations & Diagrams: N
14:55
Electron Configurations & Diagrams: O
15:24
Electron Configurations & Diagrams: F
16:25
Electron Configurations & Diagrams: Ne
17:00
Electron Configurations & Diagrams: S
18:08
Electron Configurations & Diagrams: Fe
20:08
Introduction to Valence Electrons
23:04
Valence Electrons of Oxygen
23:44
Valence Electrons of Iron
24:02
Valence Electrons of Arsenic
24:30
Valence Electrons: Exceptions
25:36
The Periodic Table
27:52
XIV. Intermolecular Forces
Vapor Pressure & Changes of State

52m 43s

Intro
0:00
Vapor Pressure and Changes of State
2:26
Intermolecular Forces Overview
2:27
Hydrogen Bonding
5:23
Heat of Vaporization
9:58
Vapor Pressure: Definition and Example
11:04
Vapor Pressures is Mostly a Function of Intermolecular Forces
17:41
Vapor Pressure Increases with Temperature
20:52
Vapor Pressure vs. Temperature: Graph and Equation
22:55
Clausius-Clapeyron Equation
31:55
Example 1
32:13
Heating Curve
35:40
Heat of Fusion
41:31
Example 2
43:45
Phase Diagrams & Solutions

31m 17s

Intro
0:00
Phase Diagrams and Solutions
0:22
Definition of a Phase Diagram
0:50
Phase Diagram Part 1: H₂O
1:54
Phase Diagram Part 2: CO₂
9:59
Solutions: Solute & Solvent
16:12
Ways of Discussing Solution Composition: Mass Percent or Weight Percent
18:46
Ways of Discussing Solution Composition: Molarity
20:07
Ways of Discussing Solution Composition: Mole Fraction
20:48
Ways of Discussing Solution Composition: Molality
21:41
Example 1: Question
22:06
Example 1: Mass Percent
24:32
Example 1: Molarity
25:53
Example 1: Mole Fraction
28:09
Example 1: Molality
29:36
Vapor Pressure of Solutions

37m 23s

Intro
0:00
Vapor Pressure of Solutions
2:07
Vapor Pressure & Raoult's Law
2:08
Example 1
5:21
When Ionic Compounds Dissolve
10:51
Example 2
12:38
Non-Ideal Solutions
17:42
Negative Deviation
24:23
Positive Deviation
29:19
Example 3
31:40
Colligatives Properties

34m 11s

Intro
0:00
Colligative Properties
1:07
Boiling Point Elevation
1:08
Example 1: Question
5:19
Example 1: Solution
6:52
Freezing Point Depression
12:01
Example 2: Question
14:46
Example 2: Solution
16:34
Osmotic Pressure
20:20
Example 3: Question
28:00
Example 3: Solution
30:16
XV. Bonding
Bonding & Lewis Structure

48m 39s

Intro
0:00
Bonding & Lewis Structure
2:23
Covalent Bond
2:24
Single Bond, Double Bond, and Triple Bond
4:11
Bond Length & Intermolecular Distance
5:51
Definition of Electronegativity
8:42
Bond Polarity
11:48
Bond Energy
20:04
Example 1
24:31
Definition of Lewis Structure
31:54
Steps in Forming a Lewis Structure
33:26
Lewis Structure Example: H₂
36:53
Lewis Structure Example: CH₄
37:33
Lewis Structure Example: NO⁺
38:43
Lewis Structure Example: PCl₅
41:12
Lewis Structure Example: ICl₄⁻
43:05
Lewis Structure Example: BeCl₂
45:07
Resonance & Formal Charge

36m 59s

Intro
0:00
Resonance and Formal Charge
0:09
Resonance Structures of NO₃⁻
0:25
Resonance Structures of NO₂⁻
12:28
Resonance Structures of HCO₂⁻
16:28
Formal Charge
19:40
Formal Charge Example: SO₄²⁻
21:32
Formal Charge Example: CO₂
31:33
Formal Charge Example: HCN
32:44
Formal Charge Example: CN⁻
33:34
Formal Charge Example: 0₃
34:43
Shapes of Molecules

41m 21s

Intro
0:00
Shapes of Molecules
0:35
VSEPR
0:36
Steps in Determining Shapes of Molecules
6:18
Linear
11:38
Trigonal Planar
11:55
Tetrahedral
12:45
Trigonal Bipyramidal
13:23
Octahedral
14:29
Table: Shapes of Molecules
15:40
Example: CO₂
21:11
Example: NO₃⁻
24:01
Example: H₂O
27:00
Example: NH₃
29:48
Example: PCl₃⁻
32:18
Example: IF₄⁺
34:38
Example: KrF₄
37:57
Hybrid Orbitals

40m 17s

Intro
0:00
Hybrid Orbitals
0:13
Introduction to Hybrid Orbitals
0:14
Electron Orbitals for CH₄
5:02
sp³ Hybridization
10:52
Example: sp³ Hybridization
12:06
sp² Hybridization
14:21
Example: sp² Hybridization
16:11
σ Bond
19:10
π Bond
20:07
sp Hybridization & Example
22:00
dsp³ Hybridization & Example
27:36
d²sp³ Hybridization & Example
30:36
Example: Predict the Hybridization and Describe the Molecular Geometry of CO
32:31
Example: Predict the Hybridization and Describe the Molecular Geometry of BF₄⁻
35:17
Example: Predict the Hybridization and Describe the Molecular Geometry of XeF₂
37:09
XVI. AP Practice Exam
AP Practice Exam: Multiple Choice, Part I

52m 34s

Intro
0:00
Multiple Choice
1:21
Multiple Choice 1
1:22
Multiple Choice 2
2:23
Multiple Choice 3
3:38
Multiple Choice 4
4:34
Multiple Choice 5
5:16
Multiple Choice 6
5:41
Multiple Choice 7
6:20
Multiple Choice 8
7:03
Multiple Choice 9
7:31
Multiple Choice 10
9:03
Multiple Choice 11
11:52
Multiple Choice 12
13:16
Multiple Choice 13
13:56
Multiple Choice 14
14:52
Multiple Choice 15
15:43
Multiple Choice 16
16:20
Multiple Choice 17
16:55
Multiple Choice 18
17:22
Multiple Choice 19
18:59
Multiple Choice 20
20:24
Multiple Choice 21
22:20
Multiple Choice 22
23:29
Multiple Choice 23
24:30
Multiple Choice 24
25:24
Multiple Choice 25
26:21
Multiple Choice 26
29:06
Multiple Choice 27
30:42
Multiple Choice 28
33:28
Multiple Choice 29
34:38
Multiple Choice 30
35:37
Multiple Choice 31
37:31
Multiple Choice 32
38:28
Multiple Choice 33
39:50
Multiple Choice 34
42:57
Multiple Choice 35
44:18
Multiple Choice 36
45:52
Multiple Choice 37
48:02
Multiple Choice 38
49:25
Multiple Choice 39
49:43
Multiple Choice 40
50:16
Multiple Choice 41
50:49
AP Practice Exam: Multiple Choice, Part II

32m 15s

Intro
0:00
Multiple Choice
0:12
Multiple Choice 42
0:13
Multiple Choice 43
0:33
Multiple Choice 44
1:16
Multiple Choice 45
2:36
Multiple Choice 46
5:22
Multiple Choice 47
6:35
Multiple Choice 48
8:02
Multiple Choice 49
10:05
Multiple Choice 50
10:26
Multiple Choice 51
11:07
Multiple Choice 52
12:01
Multiple Choice 53
12:55
Multiple Choice 54
16:12
Multiple Choice 55
18:11
Multiple Choice 56
19:45
Multiple Choice 57
20:15
Multiple Choice 58
23:28
Multiple Choice 59
24:27
Multiple Choice 60
26:45
Multiple Choice 61
29:15
AP Practice Exam: Multiple Choice, Part III

32m 50s

Intro
0:00
Multiple Choice
0:16
Multiple Choice 62
0:17
Multiple Choice 63
1:57
Multiple Choice 64
6:16
Multiple Choice 65
8:05
Multiple Choice 66
9:18
Multiple Choice 67
10:38
Multiple Choice 68
12:51
Multiple Choice 69
14:32
Multiple Choice 70
17:35
Multiple Choice 71
22:44
Multiple Choice 72
24:27
Multiple Choice 73
27:46
Multiple Choice 74
29:39
Multiple Choice 75
30:23
AP Practice Exam: Free response Part I

47m 22s

Intro
0:00
Free Response
0:15
Free Response 1: Part A
0:16
Free Response 1: Part B
4:15
Free Response 1: Part C
5:47
Free Response 1: Part D
9:20
Free Response 1: Part E. i
10:58
Free Response 1: Part E. ii
16:45
Free Response 1: Part E. iii
26:03
Free Response 2: Part A. i
31:01
Free Response 2: Part A. ii
33:38
Free Response 2: Part A. iii
35:20
Free Response 2: Part B. i
37:38
Free Response 2: Part B. ii
39:30
Free Response 2: Part B. iii
44:44
AP Practice Exam: Free Response Part II

43m 5s

Intro
0:00
Free Response
0:12
Free Response 3: Part A
0:13
Free Response 3: Part B
6:25
Free Response 3: Part C. i
11:33
Free Response 3: Part C. ii
12:02
Free Response 3: Part D
14:30
Free Response 4: Part A
21:03
Free Response 4: Part B
22:59
Free Response 4: Part C
24:33
Free Response 4: Part D
27:22
Free Response 4: Part E
28:43
Free Response 4: Part F
29:35
Free Response 4: Part G
30:15
Free Response 4: Part H
30:48
Free Response 5: Diagram
32:00
Free Response 5: Part A
34:14
Free Response 5: Part B
36:07
Free Response 5: Part C
37:45
Free Response 5: Part D
39:00
Free Response 5: Part E
40:26
AP Practice Exam: Free Response Part III

28m 36s

Intro
0:00
Free Response
0:43
Free Response 6: Part A. i
0:44
Free Response 6: Part A. ii
3:08
Free Response 6: Part A. iii
5:02
Free Response 6: Part B. i
7:11
Free Response 6: Part B. ii
9:40
Free Response 7: Part A
11:14
Free Response 7: Part B
13:45
Free Response 7: Part C
15:43
Free Response 7: Part D
16:54
Free Response 8: Part A. i
19:15
Free Response 8: Part A. ii
21:16
Free Response 8: Part B. i
23:51
Free Response 8: Part B. ii
25:07
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Lecture Comments (13)

1 answer

Last reply by: Professor Hovasapian
Wed Nov 11, 2015 4:12 AM

Post by Jason Smith on November 6, 2015

Hi professor. Any idea why the 3d orbital fills up on the 4th energy level? Like does science have any idea why this happens? Seems really bizarre!!!

4 answers

Last reply by: Professor Hovasapian
Wed Dec 11, 2013 3:20 AM

Post by Tim Zhang on December 8, 2013

In the last topic, the electron configuration of Mn end with 3d, but it is in the 4th row, so the primary number n equal 4, which means instead of 3d, I should write a 4d?

1 answer

Last reply by: Professor Hovasapian
Wed Sep 18, 2013 12:42 AM

Post by Kingsley Lunga on September 18, 2013

You make life really easy Mr Raffi

3 answers

Last reply by: Xinyuan Xing
Thu Apr 23, 2015 8:53 AM

Post by Abdirisak Ashkir on March 30, 2012

It would be better if you would explain it in a more simple way

Electron Configurations & Diagrams

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Electron Configurations & Diagrams 1:08
    • Electronic Structure of Ground State Atom
    • Order of Electron Filling
    • Electron Configurations & Diagrams: H
    • Electron Configurations & Diagrams: He
    • Electron Configurations & Diagrams: Li
    • Electron Configurations & Diagrams: Be
    • Electron Configurations & Diagrams: B
    • Electron Configurations & Diagrams: C
    • Electron Configurations & Diagrams: N
    • Electron Configurations & Diagrams: O
    • Electron Configurations & Diagrams: F
    • Electron Configurations & Diagrams: Ne
    • Electron Configurations & Diagrams: S
    • Electron Configurations & Diagrams: Fe
    • Introduction to Valence Electrons
    • Valence Electrons of Oxygen
    • Valence Electrons of Iron
    • Valence Electrons of Arsenic
    • Valence Electrons: Exceptions
    • The Periodic Table

Transcription: Electron Configurations & Diagrams

Hello, and welcome back to Educator.com, and welcome back to AP Chemistry.0000

Today, we are going to continue our discussion of electrons and electron configurations, and we are actually going to specifically talk about electron configurations and electron diagrams.0004

Last lesson, we spent a lot of time--it was pretty much just talking; we really didn't do any examples--talking about the structure of the atom, in terms of the energy levels that the electrons occupy, and the four different quantum numbers.0015

So now, we are going to get into sort of the practical aspect, from a chemical point of view--what a chemist talks about when we talk about an electron configuration.0031

So, if we say, "What is the electron configuration for silicon?", we are asking you to specify where these electrons are--the electrons that happen to be flying around silicon.0041

And then, we are going to do the diagrams, which are a little bit more specific.0052

They actually tell us--not only where they are--specifically in which sub-sublevel they are, and what the spins are of those electrons; so it's a very nice pictorial representation.0055

Let's just get started.0066

OK, so we have this notation; so we have a notation which can describe the electronic structure, the atomic structure (when we say "electronic," we are talking about the electrons), of any ground state atom.0070

"Ground state atom" just means the atom as it is found in nature.0108

Now, we can use this notation to actually represent excited states, also, and ions, as we will see in subsequent lessons.0114

But right now, we are just concerned with ground states.0120

Here we go: here is our...so we said that the primary level has an s sub-orbital, and that s can hold 2 electrons.0124

This thing--it can hold 2 electrons.0136

The second primary level has an s sublevel, and it has 3 p sublevels...I'm sorry: it has an s sublevel, and it has a p sublevel, and those p's have 3 sub-sublevels.0145

So, it can hold a total of 2, 4, 6, 8: 8 electrons.0163

The third primary has an s sublevel; it has a p, which has 3 sublevels; and it has a d sublevel, and each d has 5 sub-sublevels, which are the actual orbitals, for a total of 8, 10--it has a total of 18 electrons that it can hold.0170

This one...we have the fourth sublevel, our fourth primary: it has an s (let me put it...); it has a p, which consists of 3; it has a d...1, 2, 3, 4, 5...which consists of 5; and it has an f...1, 2, 3, 4, 5, 6, 7...this f consists of 7 sublevels.0195

The total here is going to be 32 electrons.0223

That is it: and now, what I am going to write down is the order in which these orbitals, these sublevels, actually fill in.0228

Now, what you are going to notice is: you are going to see numbers (the 1, 2, 3, 4, 5--those are the primaries); you are going to see the s, p, d, and f (those are the sublevels); but you are not going to see a specific notation for the sub-sublevels.0240

OK, so I'm only going to stop at the sublevels; and then, as a superscript, I'm going to write the total electrons in those sublevels.0252

Here is what it looks like; this is the order of filling.0262

It goes in this order: when you put electrons into...as you move down the periodic table (which--we will actually go through a periodic table later on, at the end of this lesson)--when you go through the periodic table and drop in electrons for hydrogen and helium, then lithium, then beryllium, boron, carbon, nitrogen, oxygen...you are going to fill in this order.0265

Order of electron filling--and it is going from lowest to highest energy.0289

It is: 1s2, 2s2, 2p6, 3s2, 3p6...this is just one thing you have to memorize...4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d10, 6p6, 7s2, 5f14, 6d10, 7p6.0298

Let me tell you what is going on here; let me just pick something randomly.0340

As I drop in more and more electrons as I run down the periodic table, I am filling in these orbitals; I am filling in, so the 1--the primary level, the s sublevel--I fill it in with 2 electrons, and I am done.0345

I move to the second primary: the second primary has two sublevels, s and p; in the s, I stick 2 electrons; I am done; in the p, I stick 6 electrons--I am done.0356

I move to the third level--the third: I fill in the s with 2; I fill in the p with 6.0367

Now notice, you know that the third also has a d; but it doesn't fill up yet.0374

As it turns out, it skips the d; it goes to the fourth level, fills up those two, and then returns to the d.0378

3d: it fills up 10 electrons, and then it jumps back up to 4p.0384

It fills it up with 6 electrons.0389

So, I have...some random one...4p4: OK, if I have something like that, I have the primary; I have the sublevel; and I have the total electrons in that sublevel.0391

I am not breaking this down further into sub-sublevels; I will in a minute, when I do an electron diagram--in that one, I do show you everything; but this particular notation--what we call the electron configuration--the standard electron configuration--only lists the primary and the sublevel, and the total electrons in that sublevel.0408

It does not list the sub-sublevels.0431

OK, let's see: OK, so we have all of these orbitals available; so all of these orbitals are available to us--these are just functions, and these orbitals--these energies--are available to us.0434

Electrons can go anywhere, but electrons are always going to go to the lowest energy first, and fill them up that way.0467

They are going to fill them up until they can't fill them up any more.0475

Once the s is full (it can only accommodate 2 electrons), it moves on to this s; s can only take 2--it moves on to the p; the p can take 6--once that is full, it moves on to the next primary.0477

s, then p, then s, then d, then p, then s, then d, then p; it works its way up to higher and higher energies.0488

These orbitals...now, let's start filling them up and give configurations and diagrams.0496

We will start with hydrogen: hydrogen has one electron, right?0523

Well, the configuration for that is 1s1: primary, the s sublevel, that one electron that it has goes into that s sublevel.0529

It looks like this.0539

I'm just going to do it as that: this is the electron configuration; this is the electron diagram.0545

Helium: helium has 2 electrons: 1s--the s sublevel can accommodate 2 electrons, so we put that second electron there.0554

This is that 1s2; OK.0565

Opposite spin: each orbital can accommodate 2 electrons, but the electrons have to have opposite spin.0573

They can't be both pointing up or both pointing down; they have to be opposite spin.0579

That is it: we are done with the 1s.0584

Now, we will do lithium: lithium is the third element in the periodic table.0588

Lithium has 3 electrons: its configuration is, according to the filling that I just did--the order of filling: 1s2, and then it goes to the 2s1; that is it.0594

The order was: 1s; once that is filled, you go to 2s.0609

3 electrons: these superscript numbers--they add to the total number of electrons for that atom.0611

It looks like this (now I'll actually label them).0619

How shall I do this?--I'll do 1s, and then 2...no, I don't want to...OK, I have...let me do it this way...1s; so this is the 1s; this is the 2s.0626

I have 1s2, 2s1; that is the electron diagram for lithium; this is the electron configuration for lithium.0646

OK, let's do beryllium.0656

You know what, I'm going to do this a little bit differently: this is going to be 1s; this is going to be 2s.0662

OK, it will give me a little bit cleaner, here.0676

Beryllium is next: beryllium--it has 4 electrons.0679

Well, we fill 1s2, 2s2; so we have the 1s orbital; we have the 2s orbital; and oh, by the way...1, 2, 3...we have the 2p's, also (right?--because the second primary has an s, and it also has a p); but notice, they are not filled yet.0684

They are there (actually, they are all there); but they are not filled yet.0704

We fill in that and that, and then we fill in that and that.0709

That is the electron diagram for beryllium: two electrons of opposite spin in the 1s orbital; two electrons of opposite spin in the 2s orbital.0714

OK, now, we get to our first boron: 5 electrons; we fill 1s2, 2s2, 2p1; 2+2+1=5 electrons.0724

We have: these are...I'm going to move these a little further out so I can see...these are 2p...OK, so I have: 1s here; I have 2s here; 2p here.0740

There is 1; there is 2; there is 3; there is 4; there is 5.0768

That is the electron diagram for boron: the electrons are: 2 electrons in the 1s orbital; 2 electrons in the 2s orbital; 1 electron in the 2p orbital.0773

OK, boron...carbon: we have 5 electrons...we have 6 electrons for carbon.0784

It is 1s2, 2s2, 2p2; we are just following the order of filling and adding one electron at a time--that is it.0794

The total number of electrons is just...add all of those superscripts (they are not exponents; they are superscripts).0803

So, the 1s orbital; we have a 2s orbital; the 2p is made up of 3 sub-sublevels, so we have 1 electron, 2 electron, 3 electron, 4 electron, 5 electron...notice where I put the sixth electron: I put it in the next sub-sublevel.0810

This is called Hund's rule: when you fill up a sublevel--a p--that has sub-sublevels, you have to fill...the lowest-energy configuration is when you have the most number of unpaired electrons.0831

I didn't put it here; the reason is--as it turns out, when these electrons fill out, this is a lower-energy configuration than that.0854

The same spin, but in a different sublevel: once I fill up all of my sub-sublevels, then I go back and fill in the others.0868

So again, this is always going to seek the lowest energy configuration it can.0878

And it will always do this, so when we fill in the p's and the d's and the f's, we fill them in one at a time with electrons of the same spin, and then we go back and finish it off.0882

Carbon...what is next after carbon?0893

We have nitrogen (correct?--yes); nitrogen has 7 electrons: it is 1s2, 2s2, 2p3.0897

We have a 1s orbital; we have a 2s orbital; and we have a 2p orbital, which contains 3 sublevels: 1, 2, 3, 4, 5, 6, 7--three unpaired electrons.0909

Oxygen: we have 8 electrons: we have 1s2, 2s2, 2p4; we have a 1s orbital; we have a 2s orbital; and we have 3 2p sublevels, so we have 1, 2, 3, 4, 5, 6, 7.0925

Now I go back; so here, I have 2 electrons in my 1s orbital, 2 of the electrons in the 2s orbital, 2 electrons in one of the 2p sub-sublevels, and then 1 electron each of the same spin in the other sub-sublevels of the p.0948

This is the electron configuration for oxygen--this configuration right here is what makes oxygen the particularly interesting thing that it is.0965

Hopefully, this is starting to come together; let's keep going a little bit further.0980

Let's do fluorine: fluorine has 9 electrons (I know you probably get the pattern by now; I get that, but it's nice to sort of go through it anyway).0985

It is 1s2, 2s2, 2p5; we have a 1s orbital; we have a 2s orbital; we have 1, 2, 3, 4, 5, 6, 7, 8, 9.0998

And then, we have...neon is the first noble gas that we come to.1020

10 electrons (well, helium is the first; neon is the first in the main group): 1s2, 2s2, 2p6.1027

Notice that: 1s2, 2s2, 2p6--after that--see, p can only accommodate 6 electrons; after this, we have to jump to the 3.1037

This 2s2, 2p6--later, when we get to 3s2, 3p6, 4s2, 4p6, all of the noble gas configurations end that way--the complete s and p are full.1045

That is why they are noble: they don't react, because their outer electrons (what we will define in a minute as their valence electrons)--they are complete; they don't need to be filled.1058

OK, so we have 1s; we have 2s; we have 2p; boom, boom, boom, boom--get in the habit of filling these in one at a time, even though you know that you have six of them.1068

1s2, 2s2, 2p6; OK, now let's do a random one.1086

OK, now, randomly, let's do sulfur.1092

Sulfur has 16 electrons; so, let's fill them up.1100

1s2, 2s2, 2p6, 3s2, 3p...1, 2, 3, 4.1104

2, 4, 10, 12, 16...yes, that is the electron configuration.1113

Let's go ahead and do the electron diagram: we have a 1s; we have a 2s; we have a 2p; we have a 3s; we have a 3p; and I'm going to go ahead and put a (you know what, I'm going to do it over here so I have a little more room--I have a) 3s; I have a 3p; I have a 3d; 1, 2, 3, 4, 5.1118

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16; there you go: notice, 1s2, 2s2, 2p6, 3s2, 3p4: notice this 3p4--it is the same configuration as oxygen 2p4.1150

If you look at the atom underneath sulfur, it's going to be 4p4; if you look below that, it's going to be 5p4.1175

Everything in one group of the periodic table has the same electronic configuration, but at a higher primary level; that is why they behave similarly, because they have the same electronic structure.1184

That is why their chemistry is similar--this is an explanation for why the periodic table is arranged the way that it is.1198

We will see some more of that in just a minute.1205

OK, let's do iron: let's see, iron...OK, iron has 26 electrons.1209

26 electrons: it is 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6.1218

These are going to start to get kind of long, so I am going to introduce, with iron, a shorthand notation.1235

This is the same as...I can write this as argon 4s2 3d6; and the reason is because this 1s2, 2s2, 2p6, 3s2, 3p6--that is the electron configuration for argon--the noble gas that is in the row right before it, from your perspective all the way to the right.1241

OK, so we have 1s (let's see here...yes); we have a 1s orbital; we have a 2s orbital; we have 3 2p orbitals; we have a 3s orbital; we (oops, let's make some room here--I hope we have enough) have 3 3p's; we have some 3d's (1, 2, 3, 4, 5); we have (yes, I'm definitely going to need a lot more room here) 4s, 4p's (oops, let's make sure these crazy lines don't start showing up again)--1, 2, 3; 4d--1, 2, 3, 4, 5; and we have a 4f--1, 2, 3, 4, 5, 6, 7.1268

So, we fill them up: there is 1; there is 2; 3, 4, 5, 6, 7...and you notice, I am filling in the p's one at a time.1326

Get into that habit.1337

That is 1; that is 2; 3, 4, 5, 6; now, notice, from 3s2, 3p6--the order of filling is now 4s2.1340

So, I'm going to come here to 4s2; I'm going to fill that up; and then, I'm going to go to 3d6.1351

I'm going to go to 1, 2, 3, 4, 5, 6; these orbitals are there, but they are not filled in--there are no electrons occupying them.1357

The order of filling must be maintained when you do this; the 3d orbital--yes, it is at the 3 level, but energetically, the 4s fills up before the 3d does.1369

That is why it looks the way that it does.1380

OK, so now, let's define what we mean by "valence electrons."1383

Valence electrons--it is the total number of electrons in the highest primary energy level.1389

You remember--the "highest primary"--those are the numbers (1, 2, 3, 4, 5) that are the beginning of the electron configurations (1s2, 2s2, 2p6, 3p6)...so those integers...highest primary energy level.1406

OK, so we'll just do some quick examples.1424

For oxygen, we had 1s2, 2s2, 2p4; the highest primary here is 2, and the total number of electrons is 6, so there are 6 valence electrons.1428

For iron, we had an electron configuration of argon 4s2 3d6; well, now notice: the highest primary--that is the definition (right?--"in the highest primary"); so the highest primary here is 4.1442

Even though the 3d comes afterward, and in a ground state the 4s2 is of lower energy, these are actually the valence electrons.1457

This is just 2: 2 valence electrons on iron.1465

Let's try something a little bit more interesting--how about arsenic?1470

The shorthand notation for arsenic is 4s2 3d10 4p3.1475

The highest would be the 4 primary; so we take 3+2, so we have 5 valence electrons in arsenic.1481

Notice: the 4s2 4p3 happens to be the same as...the sp configuration is the same as nitrogen, which happens to be the 2s2 2p3, which is also why arsenic is below nitrogen, in the same group as, and it has a similar chemistry as, nitrogen.1490

It is the valence electrons that determine the chemistry, and those are the electrons that we are going to be interested in.1508

Next couple of lessons, when we start talking about bonding, Lewis structures and things like that, it is the valence electrons that we are going to count.1514

So now, what I'm going to do is: I'm just going to list a couple of exceptions to the electron configuration and how we fill one at a time, because there are a couple--there are 4 elements that you should be aware of, that do things slightly differently.1522

Here are the exceptions: I mean, for the most part, they are not altogether that important; but again, they might come up, and it's good to know.1537

Chromium and molybdenum, copper and silver; this is how they are arranged in the periodic table--chromium on top of molybdenum, copper on top of silver.1549

The expected electron configuration for chromium would be (based on everything that we have done, it would be) argon, 4s2, 3d4.1561

The true electron configuration, as it turns out, is argon, 4s1, 3d5 (OK, this one--I definitely don't want these random lines here, because I want to make sure we see all of the numbers).1576

So, as it turns out, one of these electrons in the 2 actually jumps up to the 3d, so that the 3d--so that the d sublevel, which has 5 sub-sublevels--so that there is 1 electron in each sublevel; and it leaves only 1 electron in the s.1589

As it turns out, this is a lower energy configuration than that one.1607

That is why that electron that is here jumps up to this one.1612

The best way to handle it for anything chromium in that group, and copper group--basically, do the expected, and then just take one of these electrons and put it over there.1615

That is the best way to do it.1625

Copper: you are going to get an expected of argon, it should be (oh, here we go with these lines again) 4s2, 3d9; the true is actually argon, 4s1, 3d10.1626

Again, the d orbital wants so badly to be filled, when it gets that close to being filled, that it literally pulls an electron away from the 4s, and it leaves that there.1646

OK, so now that we have sort of discussed this and thrown a bunch of symbolism around, let's take a look at the periodic table and see what sort of information it can actually give us.1656

We can look at a periodic table and literally read off the electron configuration.1666

That is what is nice about this; so let's take a look at our periodic table here.1670

All right, so notice how this is arranged: we said...these numbers here (1, 2, 3, 4, 5, 6, 7)--those are the primary energy levels; those are the quantum number n.1677

These two columns (right here--1, 2)--they occupy the s suborbital.1693

1, 2, 3, 4, 5, 6: these 6 columns--they represent the p suborbital.1702

1, 2, 3, 4, 5, 6, 7, 8, 9, 10: what you know as the transition metals--they occupy the d suborbital.1714

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14: these are the f suborbitals.1724

The only reason they are down here--these actually belong right in here; so, if we were to take these and stick them right in here, it would actually end up making the periodic table two pages wide.1731

That is the only reason they put them down here: because they wanted to fit the periodic table on one page.1743

Now, when we say, "What is the electronic configuration for phosphorus?", we literally just count: 1s1, 1s2, 2s1, 2s2, 2p1, 2, 3, 4, 5, 6; 3s2, 3p1, 3p2, 3p3; so the electron configuration for phosphorus is 1s2, 2s2, 2p6, 3s2, 3p...1, 2, 3.1749

Or, the shorthand notation would be--go up and to the right--neon 3s2, 3p3.1780

Let's do the electronic configuration for manganese: OK, manganese is right over here; so we get 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d 1, 2, 3, 4, 5.1789

Our electron configuration, in shorthand notation, is argon, 4s2, 3d5.1811

We can literally just count electrons; that is what we are doing.1819

These atomic numbers right here--these are (oops, wow, that was interesting; all right, so we have 25 here)--these numbers represent the number of electrons in a neutral atom.1822

When we do the electron configuration, that is what we are doing; we are counting the number of electrons.1836

We are telling you where these electrons go; that is all that we are doing.1840

Notice: carbon: 2s2, 2p2; silicon--3s2, 3p2; germanium--4s2, 3d10, 4p2--4s2, 4p2.1844

Everything in a column has the same electron configuration, except at the next higher primary energy level.1856

Beryllium is 2s2; magnesium is 3s2; calcium is 4s2.1865

Oxygen is 2p4; sulfur is 3p4; selenium is 4p4; that is why they are arranged the way that they are arranged.1872

These fill first--the 1, the 2, the 3; 4--after the 4 fills up, and then the 3d fills up--that is why they are here; that is the whole idea.1883

This periodic table gives you a lot of information.1894

These numbers right up here: 1, 2 (notice), 3, 4, 5, 6, 7, 8--they tell you the valence electrons in that particular group.1898

Don't worry about these--these actually don't tell you the valence electrons in that group; this is an old numbering system.1908

Nowadays, the new numbering system is the Arabic numbers that you see on top: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18; that just tells you the total number of electrons that you can fill up with the s, the d, and the p.1916

This right here--these are the s electrons: the 1s, the 2s, the 3s, 4s, 5s, 6s, 7s.1932

These represent the d block--the d sublevel has 5 sub-sublevels; each one of those sub-sublevels is an orbital; each one of those orbitals contains 2 electrons.1944

5 sub-sublevels, times 2--10 electrons; that is why they are 10 long.1959

These are the p's: when you fill up the p's, the p sublevel has 3 sub-sublevels; 3 orbitals per p sublevel--that means 6 electrons in total, because each orbital can contain 2 electrons of opposite spin.1965

That is what the periodic table is doing: you can use the periodic table to do your electron structure.1983

You can use the periodic table to read off valence electrons--at least in the main group elements.1989

That is all that is going on here; actually, you can do it for this, too, because in this particular case, let's say we had iron.1999

Well, it's here; well, you know that the 4s2 is the one that is occupied; this is the 3d6.2007

Well, you know that the valence electrons are the ones in the highest primary, so it's just 2 valence electrons.2013

These numbers--again, it's an old numbering scheme; we are not going to be using that.2018

So, with that, we will go ahead and stop it here.2022

Next time, we will continue on with a discussion of...we'll get a little bit greater into depth with...electron configuration, and we'll also start talking about general notions of bonding.2025

We will spend several lessons on that.2037

So, with that, I thank you for joining us here at Educator.com.2040

We'll see you next time; goodbye.2043

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