Chemistry: Matter and Change

1
(No Transcript)
2
Chapter Menu
Electrons in Atoms
Section 5.1 Light and Quantized Energy Section
5.2 Quantum Theory and the Atom Section 5.3
Electron Configuration
Click a hyperlink or folder tab to view the
corresponding slides.
Exit
3
Section 5-1
Section 5.1 Light and Quantized Energy

• Compare the wave and particle natures of light.

• Define a quantum of energy, and explain how it is
  related to an energy change of matter.
• Contrast continuous electromagnetic spectra and
  atomic emission spectra.

radiation the rays and particles alpha
particles, beta particles, and gamma raysthat
are emitted by radioactive material
4
Section 5-1
Section 5.1 Light and Quantized Energy (cont.)
electromagnetic radiation wavelength frequency amp
litude electromagnetic spectrum
quantum Planck's constant photoelectric
effect photon atomic emission spectrum
Light, a form of electromagnetic radiation, has
characteristics of both a wave and a particle.
5
Section 5-1
The Atom and Unanswered Questions

• In Rutherford's model, the atoms mass is
  concentrated in the nucleus and electrons move
  around it.

• The model doesnt explain how the electrons were
  arranged around the nucleus.
• The model doesnt explain why negatively charged
  electrons arent pulled into the positively
  charged nucleus.

6
Section 5-1
The Atom and Unanswered Questions (cont.)

• In the early 1900s, scientists observed certain
  elements emitted visible light when heated in a
  flame.

• Analysis of the emitted light revealed that an
  elements chemical behavior is related to the
  arrangement of the electrons in its atoms.

7
Section 5-1
The Wave Nature of Light

• Visible light is a type of electromagnetic
  radiation, a form of energy that exhibits
  wave-like behavior as it travels through space.

• All waves can be described by several
  characteristics.

8
Section 5-1
The Wave Nature of Light (cont.)

• The wavelength is distance from crest to crest or
  from trough to trough.

• The frequency is the number of waves that pass a
  given point per second.
• The amplitude is the waves height from the
  origin to a crest.

9
Section 5-1
The Wave Nature of Light (cont.)
10
Section 5-1
The Wave Nature of Light (cont.)

• What relationship do you see between
  ?, v, and c?
• All waves move at the same speed!!!

11
Section 5-1
The Wave Nature of Light (cont.)

• Frequency and wavelength have an inverse
  relationship!!!

12
Section 5-1
The Wave Nature of Light (cont.)

• Sunlight, or visible light, contains a continuous
  range of wavelengths and frequencies.

• A prism separates sunlight into a continuous
  spectrum of colors pg. 138.
• The electromagnetic spectrum includes all forms
  of electromagnetic radiation pg. 139.

13
Section 5-1
The Wave Nature of Light (cont.)
14

• The Wave Nature of Light (cont.)

15

• The Wave Nature of Light (cont.)

• Visible Light

Note the trends Blue light has shorter ?, higher
v, and more energy. Red light has longer ?,
lower v, and less energy. http//www.brainpop.co
m/science/energy/electromagneticspectrum/
16
Section 5-1
The Particle Nature of Light

• The wave model of light cannot explain all of
  lights characteristics.

• Quantum as the minimum amount of energy that can
  be gained or lost by an atom.

17
Section 5-1
The Particle Nature of Light (cont.)

• The wave theory could also not explain the
  photoelectric effect - electrons are emitted from
  a metals surface when light of a certain
  frequency shines on it (how solar calculators
  work).

• http//phet.colorado.edu/en/simulation/photoelectr
  ic

18
Section 5-1
The Particle Nature of Light (cont.)

• Albert Einstein proposed in 1905 that light has a
  dual nature.

• Einstein suggested light can have wave and
  particle properties.
• A photon is a particle of electromagnetic
  radiation with no mass that carries a quantum of
  energy.
• As frequency increases, the energy of the wave
  also increases!

19
Section 5-1
Atomic Emission Spectra

• Light in a neon sign is produced when electricity
  is passed through a tube filled with neon gas and
  excites the neon atoms.

• The excited atoms emit light to release energy.

20
Section 5-1
Atomic Emission Spectra (cont.)
21
Section 5-1
Atomic Emission Spectra (cont.)

• The atomic emission spectrum of an element is the
  set of frequencies of the electromagnetic waves
  emitted by the atoms of the element.

• Each elements atomic emission spectrum is unique
  they have their own fingerprints!

22
Section 5-1
Section 5.1 Assessment
What is the smallest amount of energy that can be
gained or lost by an atom? A. electromagnetic
photon B. beta particle C. quanta
D. wave-particle

1. A
2. B
3. C
4. D

23
Section 5-1
Section 5.1 Assessment
What is a particle of electromagnetic radiation
with no mass called? A. beta particle B. alpha
particle C. quanta D. photon

1. A
2. B
3. C
4. D

24
End of Section 5-1
25
Section 5-2
Section 5.2 Quantum Theory and the Atom

• Compare the Bohr and quantum mechanical models of
  the atom.

• Explain the impact of de Broglie's wave article
  duality and the Heisenberg uncertainty principle
  on the current view of electrons in atoms.
• Identify the relationships among a hydrogen
  atom's energy levels, sublevels, and atomic
  orbitals.

atom the smallest particle of an element that
retains all the properties of that element, is
composed of electrons, protons, and neutrons.
26
Section 5-2
Section 5.2 Quantum Theory and the Atom (cont.)
ground state quantum number de Broglie
equation Heisenberg uncertainty principle
quantum mechanical model of the atom atomic
orbital principal quantum number principal energy
level energy sublevel
Wavelike properties of electrons help relate
atomic emission spectra, energy states of atoms,
and atomic orbitals.
27
Section 5-2
Bohr's Model of the Atom

• Bohr correctly predicted the frequency lines in
  hydrogens atomic emission spectrum.

• The lowest allowable energy state of an atom is
  called its ground state.
• When an atom gains energy, it is in an excited
  state.

28
Section 5-2
Bohr's Model of the Atom (cont.)

• Bohr suggested that an electron moves around the
  nucleus only in certain allowed circular orbits -
  Planetary Atomic Model.

29
Section 5-2
Bohr's Model of the Atom (cont.)

• Each orbit was given a number, called the quantum
  number.

30
Section 5-2
Bohr's Model of the Atom (cont.)

• When electrons gain energy, they can move from
  the ground state to an excited state.

• http//www.visionlearning.com/img/app/library/obje
  cts/Flash/VLObject-1347-070828110836.swf

31
Section 5-2
Bohr's Model of the Atom (cont.)
32
Section 5-2
Bohr's Model of the Atom (cont.)

• Bohrs model only worked for hydrogen, but not
  for all of the other elements.

• The behavior of electrons is still not fully
  understood, but it is known they do not move
  around the nucleus in circular orbits.

33
Section 5-2
The Quantum Mechanical Model of the Atom

• Louis de Broglie (18921987) hypothesized that
  particles, including electrons, could also have
  wavelike behaviors.

34
Section 5-2
The Quantum Mechanical Model of the Atom (cont.)

• Heisenberg showed it is impossible to take any
  measurement of an object without disturbing it.

35
Section 5-2
The Quantum Mechanical Model of the Atom (cont.)

• The Heisenberg uncertainty principle states that
  it is fundamentally impossible to know precisely
  both the velocity and position of a particle at
  the same time.
• The only quantity that can be known is the
  probability for an electron to occupy a certain
  region around the nucleus.

36
Section 5-2
The Quantum Mechanical Model of the Atom (cont.)

• Schrödinger treated electrons as waves in a model
  called the quantum mechanical model of the atom
  (electron cloud model).

• Schrödingers equation applied equally well to
  elements other than hydrogen!!!

37
Section 5-2
The Quantum Mechanical Model of the Atom (cont.)

• We now understand that atoms have a spherical
  shape where the nucleus is surrounded by the
  electron cloud.

38
Section 5-2
Section 5.2 Assessment
Which atomic suborbitals have a dumbbell shape?
A. s B. f C. p D. d

1. A
2. B
3. C
4. D

39
Section 5-2
Section 5.2 Assessment
Who proposed that particles could also exhibit
wavelike behaviors? A. Bohr B. Einstein
C. Rutherford D. de Broglie

1. A
2. B
3. C
4. D

40
End of Section 5-2
41
Section 5-3
Section 5.3 Electron Configuration

• Apply the Pauli exclusion principle, the aufbau
  principle, and Hund's rule to write electron
  configurations using orbital diagrams and
  electron configuration notation.

• Define valence electrons, and draw electron-dot
  structures representing an atom's valence
  electrons.

electron a negatively charged, fast-moving
particle with an extremely small mass that is
found in all forms of matter and moves through
the empty space surrounding an atom's nucleus
42
Section 5-3
Section 5.3 Electron Configuration (cont.)
valence electrons electron-dot structure
Electrons are arranged in energy levels in the
electron cloud.
43
Section 5-3
Ground-State Electron Configuration

• In a neutral atom, the number of protons equals
  the number of electrons.
• These electrons are arranged in energy levels
  around the nucleus.

44
Section 5-3
Ground-State Electron Configuration

• Energy increases as levels move away from the
  nucleus.
• Electrons must fill the lower energy levels, then
  move to higher energy levels.

45
Section 5-3
Ground-State Electron Configuration (cont.)

• Maximum number of e- in each energy level
• Level 1 maximum of 2 e-
• Level 2 maximum of 8 e-
• Level 3 maximum of 18 e-
• Level 4 maximum of 32 e-
• Level 5 maximum of 50 e-

46
Section 5-3
Ground-State Electron Configuration (cont.)

• In energy level 3 and higher, several additional
  electrons can be added to inner sublevels.
• This leaves the outer level with a maximum of
  only 8 e-.
• These are called valence electrons!

47
Section 5-3
Valence Electrons

• Valence electrons are defined as electrons in the
  atoms outer energy level.

48
Section 5-3
Valence Electrons

• An elements valence electrons determine the
  chemical properties of the element.

• Electron-dot structure consists of the elements
  symbol representing the nucleus and inner
  electrons, surrounded by dots representing the
  elements valence electrons.

49
Section 5-3
Section 5.3 Assessment
In the ground state, which orbital does an atoms
electrons occupy? A. the highest
available B. the lowest available C. the n 0
orbital D. the d suborbital

1. A
2. B
3. C
4. D

50
Section 5-3
Section 5.3 Assessment
The outermost electrons of an atom are called
what? A. suborbitals B. orbitals C. ground
state electrons D. valence electrons

1. A
2. B
3. C
4. D

51
End of Section 5-3
52
Resources Menu
Chemistry Online Study Guide Chapter
Assessment Standardized Test Practice Image
Bank Concepts in Motion
53
Study Guide 1
Section 5.1 Light and Quantized Energy
Key Concepts

• All waves are defined by their wavelengths,
  frequencies, amplitudes, and speeds. c ??

• In a vacuum, all electromagnetic waves travel at
  the speed of light.
• All electromagnetic waves have both wave and
  particle properties.
• Matter emits and absorbs energy in
  quanta.Equantum h?

54
Study Guide 1
Section 5.1 Light and Quantized Energy (cont.)
Key Concepts

• White light produces a continuous spectrum. An
  elements emission spectrum consists of a series
  of lines of individual colors.

55
Study Guide 2
Section 5.2 Quantum Theory and the Atom
Key Concepts

• Bohrs atomic model attributes hydrogens
  emission spectrum to electrons dropping from
  higher-energy to lower-energy orbits. ?E E
  higher-energy orbit - E lower-energy orbit E
  photon h?

• The de Broglie equation relates a particles
  wavelength to its mass, its velocity, and
  Plancks constant. ? h / m?
• The quantum mechanical model of the atom assumes
  that electrons have wave properties.
• Electrons occupy three-dimensional regions of
  space called atomic orbitals.

56
Study Guide 3
Section 5.3 Electron Configuration
Key Concepts

• The arrangement of electrons in an atom is called
  the atoms electron configuration.

• Electron configurations are defined by the aufbau
  principle, the Pauli exclusion principle, and
  Hunds rule.
• An elements valence electrons determine the
  chemical properties of the element.
• Electron configurations can be represented using
  orbital diagrams, electron configuration
  notation, and electron-dot structures.

57
Chapter Assessment 1
The shortest distance from equivalent points on a
continuous wave is the A. frequency
B. wavelength C. amplitude D. crest

1. A
2. B
3. C
4. D

58
Chapter Assessment 2
The energy of a wave increases as ____.
A. frequency decreases B. wavelength decreases
C. wavelength increases D. distance increases

1. A
2. B
3. C
4. D

59
Chapter Assessment 3
Atoms move in circular orbits in which atomic
model? A. quantum mechanical model
B. Rutherfords model C. Bohrs model
D. plum-pudding model

1. A
2. B
3. C
4. D

60
Chapter Assessment 4
It is impossible to know precisely both the
location and velocity of an electron at the same
time because A. the Pauli exclusion principle
B. the dual nature of light C. electrons travel
in waves D. the Heisenberg uncertainty
principle

1. A
2. B
3. C
4. D

61
Chapter Assessment 5
How many valence electrons does neon have? A. 0
B. 1 C. 2 D. 3

1. A
2. B
3. C
4. D

62
STP 1
Spherical orbitals belong to which sublevel?
A. s B. p C. d D. f

1. A
2. B
3. C
4. D

63
STP 2
What is the maximum number of electrons the 1s
orbital can hold? A. 10 B. 2 C. 8 D. 1

1. A
2. B
3. C
4. D

64
STP 3
In order for two electrons to occupy the same
orbital, they must A. have opposite charges
B. have opposite spins C. have the same spin
D. have the same spin and charge

1. A
2. B
3. C
4. D

65
STP 4
How many valence electrons does boron contain?
A. 1 B. 2 C. 3 D. 5

1. A
2. B
3. C
4. D

66
STP 5
What is a quantum? A. another name for an atom
B. the smallest amount of energy that can be
gained or lost by an atom C. the ground state
of an atom D. the excited state of an atom

1. A
2. B
3. C
4. D

67
IB Menu
Click on an image to enlarge.
68
IB 1
69
IB 2
70
IB 3
71
IB 4
72
IB 5
73
IB 6
74
IB 7
75
IB 8
76
IB 9
77
IB 10
78
IB 11
79
IB 12
80
IB 13
81
IB 14
82
IB 15
83
IB 16
84
IB 17
85
IB 18
86
IB 19
87
IB 20
88
IB 21
89
IB 22
90
CIM
Figure 5.11 Balmer Series Figure 5.12 Electron
Transitions Table 5.4 Electron Configurations
and Orbital Diagrams for Elements 110 Table 5.6
Electron Configurations and Dot Structures
91
Help
Click any of the background top tabs to display
the respective folder.
Within the Chapter Outline, clicking a section
tab on the right side of the screen will bring
you to the first slide in each respective section.
Simple navigation buttons will allow you to
progress to the next slide or the previous slide.
The Chapter Resources Menu will allow you to
access chapter specific resources from the
Chapter Menu or any Chapter Outline slide. From
within any feature, click the Resources tab to
return to this slide.
The Return button will allow you to return to
the slide that you were viewing when you clicked
either the Resources or Help tab.
To exit the presentation, click the Exit button
on the Chapter Menu slide or hit Escape Esc on
your keyboards while viewing any Chapter Outline
slide.
92
End of Custom Shows
This slide is intentionally blank.